diff --git a/.idea/gradle.xml b/.idea/gradle.xml
index 08300ac..f261649 100644
--- a/.idea/gradle.xml
+++ b/.idea/gradle.xml
@@ -5,7 +5,7 @@
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>
         <option name="externalProjectPath" value="$PROJECT_DIR$" />
-        <option name="gradleHome" value="" />
+        <option name="gradleJvm" value="openjdk-21" />
         <option name="modules">
           <set>
             <option value="$PROJECT_DIR$" />
diff --git a/.idea/misc.xml b/.idea/misc.xml
index f16dea7..32d884a 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -4,7 +4,7 @@
   <component name="FrameworkDetectionExcludesConfiguration">
     <file type="web" url="file://$PROJECT_DIR$" />
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="21" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="openjdk-21" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>
\ No newline at end of file
diff --git a/.idea/sqldialects.xml b/.idea/sqldialects.xml
new file mode 100644
index 0000000..e4024dd
--- /dev/null
+++ b/.idea/sqldialects.xml
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="SqlDialectMappings">
+    <file url="file://$PROJECT_DIR$/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/RawTransactionValueGroupRepository.java" dialect="GenericSQL" />
+    <file url="PROJECT" dialect="PostgreSQL" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/Common/build.gradle b/Common/build.gradle
index 99eba84..6f33e3e 100644
--- a/Common/build.gradle
+++ b/Common/build.gradle
@@ -11,6 +11,7 @@ repositories {
 
 dependencies {
     implementation 'jakarta.persistence:jakarta.persistence-api:3.1.0'
+    implementation 'org.springframework:spring-web:6.1.1'
 
     testImplementation platform('org.junit:junit-bom:5.9.1')
     testImplementation 'org.junit.jupiter:junit-jupiter'
diff --git a/Common/src/main/java/dev/mvvasilev/common/controller/AbstractRestController.java b/Common/src/main/java/dev/mvvasilev/common/controller/AbstractRestController.java
index 3a266a6..62f16c4 100644
--- a/Common/src/main/java/dev/mvvasilev/common/controller/AbstractRestController.java
+++ b/Common/src/main/java/dev/mvvasilev/common/controller/AbstractRestController.java
@@ -2,21 +2,40 @@ package dev.mvvasilev.common.controller;
 
 import dev.mvvasilev.common.web.APIErrorDTO;
 import dev.mvvasilev.common.web.APIResponseDTO;
+import dev.mvvasilev.common.web.CrudResponseDTO;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
 
 import java.util.List;
 
-public class AbstractRestController {
+public abstract class AbstractRestController {
 
-    protected <T> APIResponseDTO<T> withStatus(int statusCode, String statusText, T body) {
-        return new APIResponseDTO<>(body, null, statusCode, statusText);
+    protected <T> ResponseEntity<APIResponseDTO<T>> withStatus(HttpStatus status, T body) {
+        return ResponseEntity.status(status).body(new APIResponseDTO<>(body, null, status.value(), status.getReasonPhrase()));
     }
 
-    protected <T> APIResponseDTO<T> withSingleError(int statusCode, String statusText, String errorMessage, String errorCode, String stacktrace) {
-        return new APIResponseDTO<>(null, List.of(new APIErrorDTO(errorMessage, errorCode, stacktrace)), statusCode, statusText);
+    protected <T> ResponseEntity<APIResponseDTO<T>> withSingleError(HttpStatus status, String errorMessage, String errorCode, String stacktrace) {
+        return ResponseEntity.status(status).body(new APIResponseDTO<>(null, List.of(new APIErrorDTO(errorMessage, errorCode, stacktrace)), status.value(), status.getReasonPhrase()));
     }
 
-    protected <T> APIResponseDTO<T> ok(T body) {
-        return withStatus(200, "ok", body);
+    protected <T> ResponseEntity<APIResponseDTO<T>> ok(T body) {
+        return withStatus(HttpStatus.OK, body);
+    }
+
+    protected <T> ResponseEntity<APIResponseDTO<Object>> emptySuccess() {
+        return withStatus(HttpStatus.OK, null);
+    }
+
+    protected <T> ResponseEntity<APIResponseDTO<CrudResponseDTO>> created(Long id) {
+        return withStatus(HttpStatus.CREATED, new CrudResponseDTO(id, null));
+    }
+
+    protected <T> ResponseEntity<APIResponseDTO<CrudResponseDTO>> updated(Integer affectedRows) {
+        return withStatus(HttpStatus.OK, new CrudResponseDTO(null, affectedRows));
+    }
+
+    protected <T> ResponseEntity<APIResponseDTO<CrudResponseDTO>> deleted(Integer affectedRows) {
+        return withStatus(HttpStatus.OK, new CrudResponseDTO(null, affectedRows));
     }
 
 }
diff --git a/Common/src/main/java/dev/mvvasilev/common/data/AbstractEnumConverter.java b/Common/src/main/java/dev/mvvasilev/common/data/AbstractEnumConverter.java
new file mode 100644
index 0000000..216ea4d
--- /dev/null
+++ b/Common/src/main/java/dev/mvvasilev/common/data/AbstractEnumConverter.java
@@ -0,0 +1,31 @@
+package dev.mvvasilev.common.data;
+
+import jakarta.persistence.AttributeConverter;
+import jakarta.persistence.Converter;
+
+@Converter
+public abstract class AbstractEnumConverter<T extends Enum<T> & PersistableEnum<E>, E> implements AttributeConverter<T, E> {
+    private final Class<T> clazz;
+
+    public AbstractEnumConverter(Class<T> clazz) {
+        this.clazz = clazz;
+    }
+
+    @Override
+    public E convertToDatabaseColumn(T attribute) {
+        return attribute != null ? attribute.value() : null;
+    }
+
+    @Override
+    public T convertToEntityAttribute(E dbData) {
+        T[] enums = clazz.getEnumConstants();
+
+        for (T e : enums) {
+            if (e.value().equals(dbData)) {
+                return e;
+            }
+        }
+
+        throw new UnsupportedOperationException();
+    }
+}
\ No newline at end of file
diff --git a/Common/src/main/java/dev/mvvasilev/common/data/PersistableEnum.java b/Common/src/main/java/dev/mvvasilev/common/data/PersistableEnum.java
new file mode 100644
index 0000000..0b951c1
--- /dev/null
+++ b/Common/src/main/java/dev/mvvasilev/common/data/PersistableEnum.java
@@ -0,0 +1,7 @@
+package dev.mvvasilev.common.data;
+
+public interface PersistableEnum<T> {
+
+    T value();
+
+}
diff --git a/Common/src/main/java/dev/mvvasilev/common/data/UserOwned.java b/Common/src/main/java/dev/mvvasilev/common/data/UserOwned.java
new file mode 100644
index 0000000..45a15b5
--- /dev/null
+++ b/Common/src/main/java/dev/mvvasilev/common/data/UserOwned.java
@@ -0,0 +1,7 @@
+package dev.mvvasilev.common.data;
+
+public interface UserOwned extends DatabaseStorable {
+
+    Integer getUserId();
+
+}
diff --git a/Common/src/main/java/dev/mvvasilev/common/exceptions/CommonFinancesException.java b/Common/src/main/java/dev/mvvasilev/common/exceptions/CommonFinancesException.java
index d15e631..1608f6b 100644
--- a/Common/src/main/java/dev/mvvasilev/common/exceptions/CommonFinancesException.java
+++ b/Common/src/main/java/dev/mvvasilev/common/exceptions/CommonFinancesException.java
@@ -1,4 +1,12 @@
 package dev.mvvasilev.common.exceptions;
 
 public class CommonFinancesException extends RuntimeException {
+
+    public CommonFinancesException(String message) {
+        super(message);
+    }
+
+    public CommonFinancesException(String messageTemplate, Object... replacements) {
+        super(String.format(messageTemplate, replacements));
+    }
 }
diff --git a/Common/src/main/java/dev/mvvasilev/common/web/CrudResponseDTO.java b/Common/src/main/java/dev/mvvasilev/common/web/CrudResponseDTO.java
new file mode 100644
index 0000000..25f28bf
--- /dev/null
+++ b/Common/src/main/java/dev/mvvasilev/common/web/CrudResponseDTO.java
@@ -0,0 +1,8 @@
+package dev.mvvasilev.common.web;
+
+public record CrudResponseDTO (
+        Long createdId,
+        Integer affectedRows
+
+) {
+}
diff --git a/PersonalFinancesService/build.gradle b/PersonalFinancesService/build.gradle
index 86cf4d5..6440a5e 100644
--- a/PersonalFinancesService/build.gradle
+++ b/PersonalFinancesService/build.gradle
@@ -24,9 +24,9 @@ ext['spring-security.version']='6.2.0'
 dependencies {
 	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
 	implementation 'org.springframework.boot:spring-boot-starter-oauth2-resource-server'
-	implementation 'org.springframework.boot:spring-boot-starter-security'
+	// implementation 'org.springframework.boot:spring-boot-starter-security'
+	implementation 'org.springframework.boot:spring-boot-starter-validation'
 	implementation 'org.springframework.boot:spring-boot-starter-web'
-	implementation 'org.springframework.boot:spring-boot-starter-actuator'
 
 	implementation 'org.flywaydb:flyway-core'
 	implementation 'org.springdoc:springdoc-openapi-starter-common:2.3.0'
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/configuration/SecurityConfiguration.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/configuration/SecurityConfiguration.java
index 98e609e..197e34e 100644
--- a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/configuration/SecurityConfiguration.java
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/configuration/SecurityConfiguration.java
@@ -11,9 +11,11 @@ import org.springframework.security.oauth2.jwt.JwtDecoders;
 import org.springframework.security.oauth2.server.resource.web.BearerTokenResolver;
 import org.springframework.security.oauth2.server.resource.web.DefaultBearerTokenResolver;
 import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
 import org.springframework.web.filter.CommonsRequestLoggingFilter;
 
 @Configuration
+@EnableTransactionManagement
 public class SecurityConfiguration {
 
     @Value("${jwt.issuer-url}")
@@ -23,8 +25,7 @@ public class SecurityConfiguration {
             "/v3/api-docs/**",
             "/swagger-ui/**",
             "/v2/api-docs/**",
-            "/swagger-resources/**",
-            "/actuator/**"
+            "/swagger-resources/**"
     };
 
     @Bean
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/CategoriesController.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/CategoriesController.java
new file mode 100644
index 0000000..16bce12
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/CategoriesController.java
@@ -0,0 +1,85 @@
+package dev.mvvasilev.finances.controllers;
+
+import dev.mvvasilev.common.controller.AbstractRestController;
+import dev.mvvasilev.common.web.APIResponseDTO;
+import dev.mvvasilev.common.web.CrudResponseDTO;
+import dev.mvvasilev.finances.dtos.*;
+import dev.mvvasilev.finances.services.CategoryService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.security.core.Authentication;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.Collection;
+
+@RestController
+@RequestMapping("/categories")
+public class CategoriesController extends AbstractRestController {
+
+    final private CategoryService categoryService;
+
+    @Autowired
+    public CategoriesController(CategoryService categoryService) {
+        this.categoryService = categoryService;
+    }
+
+    @PostMapping
+    public ResponseEntity<APIResponseDTO<CrudResponseDTO>> createCategory(
+            @RequestBody CreateCategoryDTO dto,
+            Authentication authentication
+    ) {
+        return created(categoryService.createForUser(dto, Integer.parseInt(authentication.getName())));
+    }
+
+    @GetMapping
+    public ResponseEntity<APIResponseDTO<Collection<CategoryDTO>>> listCategories(Authentication authentication) {
+        return ok(categoryService.listForUser(Integer.parseInt(authentication.getName())));
+    }
+
+    @PutMapping("/{categoryId}")
+    @PreAuthorize("@authService.isOwner(#categoryId, T(dev.mvvasilev.finances.entity.TransactionCategory))")
+    public ResponseEntity<APIResponseDTO<CrudResponseDTO>> updateCategory(
+            @PathVariable("categoryId") Long categoryId,
+            @RequestBody UpdateCategoryDTO dto
+    ) {
+        return updated(categoryService.update(categoryId, dto));
+    }
+
+    @DeleteMapping("/{categoryId}")
+    @PreAuthorize("@authService.isOwner(#categoryId, T(dev.mvvasilev.finances.entity.TransactionCategory))")
+    public ResponseEntity<APIResponseDTO<CrudResponseDTO>> deleteCategory(@PathVariable("categoryId") Long categoryId) {
+        return deleted(categoryService.delete(categoryId));
+    }
+
+    @GetMapping("/{categoryId}/rules")
+    @PreAuthorize("@authService.isOwner(#categoryId, T(dev.mvvasilev.finances.entity.TransactionCategory))")
+    public ResponseEntity<APIResponseDTO<Collection<CategorizationDTO>>> fetchCategorizationRules(@PathVariable("categoryId") Long categoryId) {
+        return ok(categoryService.fetchCategorizationRules(categoryId));
+    }
+
+    @PostMapping("/{categoryId}/rules")
+    @PreAuthorize("@authService.isOwner(#categoryId, T(dev.mvvasilev.finances.entity.TransactionCategory))")
+    public ResponseEntity<APIResponseDTO<CrudResponseDTO>> createCategorizationRule(
+            @PathVariable("categoryId") Long categoryId,
+            @RequestBody Collection<CreateCategorizationDTO> dto
+    ) {
+        return created(categoryService.createCategorizationRule(categoryId, dto));
+    }
+
+    @DeleteMapping("/{categoryId}/rules/{ruleId}")
+    @PreAuthorize("@authService.isOwner(#categoryId, T(dev.mvvasilev.finances.entity.TransactionCategory))")
+    public ResponseEntity<APIResponseDTO<CrudResponseDTO>> deleteCategorizationRule(
+            @PathVariable("categoryId") Long categoryId,
+            @PathVariable("ruleId") Long ruleId
+    ) {
+        return deleted(categoryService.deleteCategorizationRule(ruleId));
+    }
+
+    @PostMapping("/categorize")
+    public ResponseEntity<APIResponseDTO<Object>> categorizeTransactions(Authentication authentication) {
+        categoryService.categorizeForUser(Integer.parseInt(authentication.getName()));
+        return emptySuccess();
+    }
+
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/DebugController.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/DebugController.java
index 6fe1eeb..5f8d462 100644
--- a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/DebugController.java
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/DebugController.java
@@ -13,6 +13,6 @@ import org.springframework.web.bind.annotation.RestController;
 public class DebugController extends AbstractRestController {
     @GetMapping("/token")
     public ResponseEntity<APIResponseDTO<String>> fetchToken(@RequestHeader("Authorization") String authHeader) {
-        return ResponseEntity.ofNullable(ok(authHeader));
+        return ok(authHeader);
     }
 }
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/ProcessedTransactionsController.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/ProcessedTransactionsController.java
new file mode 100644
index 0000000..0e10d64
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/ProcessedTransactionsController.java
@@ -0,0 +1,19 @@
+package dev.mvvasilev.finances.controllers;
+
+import dev.mvvasilev.common.controller.AbstractRestController;
+import dev.mvvasilev.common.web.APIResponseDTO;
+import dev.mvvasilev.finances.enums.ProcessedTransactionField;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/processed-transactions")
+public class ProcessedTransactionsController extends AbstractRestController {
+
+    @GetMapping("/fields")
+    public ResponseEntity<APIResponseDTO<ProcessedTransactionField[]>> fetchFields() {
+        return ok(ProcessedTransactionField.values());
+    }
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/StatementsController.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/StatementsController.java
index fa8baa0..fff45cf 100644
--- a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/StatementsController.java
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/controllers/StatementsController.java
@@ -2,14 +2,16 @@ package dev.mvvasilev.finances.controllers;
 
 import dev.mvvasilev.common.controller.AbstractRestController;
 import dev.mvvasilev.common.web.APIResponseDTO;
+import dev.mvvasilev.common.web.CrudResponseDTO;
+import dev.mvvasilev.finances.dtos.CreateTransactionMappingDTO;
+import dev.mvvasilev.finances.dtos.TransactionMappingDTO;
 import dev.mvvasilev.finances.dtos.TransactionValueGroupDTO;
 import dev.mvvasilev.finances.dtos.UploadedStatementDTO;
 import dev.mvvasilev.finances.services.StatementsService;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.http.HttpStatus;
-import org.springframework.http.HttpStatusCode;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
+import org.springframework.security.access.prepost.PreAuthorize;
 import org.springframework.security.core.Authentication;
 import org.springframework.web.bind.annotation.*;
 import org.springframework.web.multipart.MultipartFile;
@@ -21,7 +23,7 @@ import java.util.Collection;
 @RequestMapping("/statements")
 public class StatementsController extends AbstractRestController {
 
-    private StatementsService statementsService;
+    final private StatementsService statementsService;
 
     @Autowired
     public StatementsController(StatementsService statementsService) {
@@ -30,33 +32,60 @@ public class StatementsController extends AbstractRestController {
 
     @GetMapping
     public ResponseEntity<APIResponseDTO<Collection<UploadedStatementDTO>>> fetchStatements(Authentication authentication) {
-        return ResponseEntity.ofNullable(
-                ok(statementsService.fetchStatementsForUser(Integer.parseInt(authentication.getName())))
-        );
+        return ok(statementsService.fetchStatementsForUser(Integer.parseInt(authentication.getName())));
     }
 
     @GetMapping("/{statementId}/transactionValueGroups")
-    public ResponseEntity<APIResponseDTO<Collection<TransactionValueGroupDTO>>> fetchTransactionValueGroups(@PathVariable("statementId") Long statementId, Authentication authentication) {
-        return ResponseEntity.ofNullable(ok(
-                statementsService.fetchTransactionValueGroupsForUserStatement(statementId, Integer.parseInt(authentication.getName()))
-        ));
+    @PreAuthorize("@authService.isOwner(#statementId, T(dev.mvvasilev.finances.entity.RawStatement))")
+    public ResponseEntity<APIResponseDTO<Collection<TransactionValueGroupDTO>>> fetchTransactionValueGroups(
+            @PathVariable("statementId") Long statementId
+    ) {
+        return ok(statementsService.fetchTransactionValueGroupsForUserStatement(statementId));
+    }
+
+    @GetMapping("/{statementId}/mappings")
+    @PreAuthorize("@authService.isOwner(#statementId, T(dev.mvvasilev.finances.entity.RawStatement))")
+    public ResponseEntity<APIResponseDTO<Collection<TransactionMappingDTO>>> fetchTransactionMappings(
+            @PathVariable("statementId") Long statementId
+    ) {
+        return ok(statementsService.fetchMappingsForStatement(statementId));
+    }
+
+    @PostMapping("/{statementId}/mappings")
+    @PreAuthorize("@authService.isOwner(#statementId, T(dev.mvvasilev.finances.entity.RawStatement))")
+    public ResponseEntity<APIResponseDTO<Collection<CrudResponseDTO>>> createTransactionMappings(
+            @PathVariable("statementId") Long statementId,
+            @RequestBody Collection<CreateTransactionMappingDTO> body
+    ) {
+        return ok(statementsService.createTransactionMappingsForStatement(statementId, body));
+    }
+
+
+    @PostMapping("/{statementId}/process")
+    @PreAuthorize("@authService.isOwner(#statementId, T(dev.mvvasilev.finances.entity.RawStatement))")
+    public ResponseEntity<APIResponseDTO<Object>> processTransactions(@PathVariable("statementId") Long statementId) {
+        statementsService.processStatement(statementId);
+        return emptySuccess();
     }
 
     @DeleteMapping("/{statementId}")
-    public ResponseEntity<APIResponseDTO> deleteStatement(@PathVariable("statementId")  Long statementId, Authentication authentication) {
-        statementsService.deleteStatement(statementId, Integer.parseInt(authentication.getName()));
-        return ResponseEntity.ofNullable(ok(null));
+    @PreAuthorize("@authService.isOwner(#statementId, T(dev.mvvasilev.finances.entity.RawStatement))")
+    public ResponseEntity<APIResponseDTO<Object>> deleteStatement(@PathVariable("statementId")  Long statementId) {
+        statementsService.deleteStatement(statementId);
+
+        return emptySuccess();
     }
 
     @PostMapping(value = "/uploadSheet", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
-    public ResponseEntity<APIResponseDTO<Integer>> uploadStatement(@RequestParam("file") MultipartFile file, Authentication authentication) throws IOException {
+    public ResponseEntity<APIResponseDTO<Object>> uploadStatement(@RequestParam("file") MultipartFile file, Authentication authentication) throws IOException {
         statementsService.uploadStatementFromExcelSheetForUser(
                 file.getOriginalFilename(),
                 file.getContentType(),
                 file.getInputStream(),
                 Integer.parseInt(authentication.getName())
         );
-        return ResponseEntity.ofNullable(ok(1));
+
+        return emptySuccess();
     }
 
 }
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CategorizationDTO.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CategorizationDTO.java
new file mode 100644
index 0000000..feacc82
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CategorizationDTO.java
@@ -0,0 +1,30 @@
+package dev.mvvasilev.finances.dtos;
+
+import dev.mvvasilev.finances.enums.CategorizationRule;
+
+import java.time.LocalDateTime;
+
+public record CategorizationDTO(
+        Long id,
+
+        CategorizationRule rule,
+
+        String stringValue,
+
+        Double numericGreaterThan,
+
+        Double numericLessThan,
+
+        Double numericValue,
+
+        LocalDateTime timestampGreaterThan,
+
+        LocalDateTime timestampLessThan,
+
+        Boolean booleanValue,
+
+        CategorizationDTO left,
+
+        CategorizationDTO right
+) {
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CategoryDTO.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CategoryDTO.java
new file mode 100644
index 0000000..78b43d6
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CategoryDTO.java
@@ -0,0 +1,7 @@
+package dev.mvvasilev.finances.dtos;
+
+public record CategoryDTO(
+        Long id,
+        String name
+) {
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CreateCategorizationDTO.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CreateCategorizationDTO.java
new file mode 100644
index 0000000..205bc57
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CreateCategorizationDTO.java
@@ -0,0 +1,36 @@
+package dev.mvvasilev.finances.dtos;
+
+import dev.mvvasilev.finances.enums.CategorizationRule;
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Null;
+import org.hibernate.validator.constraints.Length;
+
+import java.time.LocalDateTime;
+
+public record CreateCategorizationDTO (
+        @NotNull
+        CategorizationRule rule,
+
+        @Length(max = 1024)
+        String stringValue,
+
+        Double numericGreaterThan,
+
+        Double numericLessThan,
+
+        Double numericValue,
+
+        LocalDateTime timestampGreaterThan,
+
+        LocalDateTime timestampLessThan,
+
+        Boolean booleanValue,
+
+        @Valid
+        CreateCategorizationDTO left,
+
+        @Valid
+        CreateCategorizationDTO right
+) {
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CreateCategoryDTO.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CreateCategoryDTO.java
new file mode 100644
index 0000000..596ad30
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CreateCategoryDTO.java
@@ -0,0 +1,11 @@
+package dev.mvvasilev.finances.dtos;
+
+import jakarta.validation.constraints.NotNull;
+import org.hibernate.validator.constraints.Length;
+
+public record CreateCategoryDTO (
+        @Length(max = 255)
+        @NotNull
+        String name
+) {
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CreateTransactionMappingDTO.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CreateTransactionMappingDTO.java
new file mode 100644
index 0000000..181c377
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/CreateTransactionMappingDTO.java
@@ -0,0 +1,12 @@
+package dev.mvvasilev.finances.dtos;
+
+import dev.mvvasilev.finances.enums.ProcessedTransactionField;
+import jakarta.validation.constraints.NotNull;
+
+public record CreateTransactionMappingDTO(
+        @NotNull
+        Long rawTransactionValueGroupId,
+        @NotNull
+        ProcessedTransactionField field
+) {
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/TransactionMappingDTO.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/TransactionMappingDTO.java
new file mode 100644
index 0000000..636235d
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/TransactionMappingDTO.java
@@ -0,0 +1,10 @@
+package dev.mvvasilev.finances.dtos;
+
+import dev.mvvasilev.finances.enums.ProcessedTransactionField;
+
+public record TransactionMappingDTO(
+        Long id,
+        Long rawTransactionValueGroupId,
+        ProcessedTransactionField processedTransactionField
+) {
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/UpdateCategoryDTO.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/UpdateCategoryDTO.java
new file mode 100644
index 0000000..511f470
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/dtos/UpdateCategoryDTO.java
@@ -0,0 +1,11 @@
+package dev.mvvasilev.finances.dtos;
+
+import jakarta.validation.constraints.NotNull;
+import org.hibernate.validator.constraints.Length;
+
+public record UpdateCategoryDTO (
+        @NotNull
+        @Length(max = 255)
+        String name
+) {
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/Categorization.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/Categorization.java
new file mode 100644
index 0000000..b42f58e
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/Categorization.java
@@ -0,0 +1,152 @@
+package dev.mvvasilev.finances.entity;
+
+import dev.mvvasilev.common.data.AbstractEntity;
+import dev.mvvasilev.common.data.UserOwned;
+import dev.mvvasilev.finances.enums.CategorizationRule;
+import dev.mvvasilev.finances.enums.ProcessedTransactionField;
+import jakarta.persistence.Convert;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Table;
+
+import java.time.LocalDateTime;
+
+@Entity
+@Table(schema = "categories")
+public class Categorization extends AbstractEntity implements UserOwned {
+
+    private Integer userId;
+
+    @Convert(converter = ProcessedTransactionField.JpaConverter.class)
+    private ProcessedTransactionField ruleBasedOn;
+
+    @Convert(converter = CategorizationRule.JpaConverter.class)
+    private CategorizationRule categorizationRule;
+
+    private String stringValue;
+
+    private double numericGreaterThan;
+
+    private double numericLessThan;
+
+    private double numericValue;
+
+    private LocalDateTime timestampGreaterThan;
+
+    private LocalDateTime timestampLessThan;
+
+    private boolean booleanValue;
+
+    private Long categoryId;
+
+    private Long leftCategorizationId;
+
+    private Long rightCategorizationId;
+
+    public Categorization() {
+    }
+
+    @Override
+    public Integer getUserId() {
+        return null;
+    }
+
+    public void setUserId(Integer userId) {
+        this.userId = userId;
+    }
+
+    public ProcessedTransactionField getRuleBasedOn() {
+        return ruleBasedOn;
+    }
+
+    public void setRuleBasedOn(ProcessedTransactionField ruleBasedOn) {
+        this.ruleBasedOn = ruleBasedOn;
+    }
+
+    public CategorizationRule getCategorizationRule() {
+        return categorizationRule;
+    }
+
+    public void setCategorizationRule(CategorizationRule categorizationRule) {
+        this.categorizationRule = categorizationRule;
+    }
+
+    public String getStringValue() {
+        return stringValue;
+    }
+
+    public void setStringValue(String stringValue) {
+        this.stringValue = stringValue;
+    }
+
+    public double getNumericGreaterThan() {
+        return numericGreaterThan;
+    }
+
+    public void setNumericGreaterThan(double numericGreaterThan) {
+        this.numericGreaterThan = numericGreaterThan;
+    }
+
+    public double getNumericLessThan() {
+        return numericLessThan;
+    }
+
+    public void setNumericLessThan(double numericLessThan) {
+        this.numericLessThan = numericLessThan;
+    }
+
+    public double getNumericValue() {
+        return numericValue;
+    }
+
+    public void setNumericValue(double numericValue) {
+        this.numericValue = numericValue;
+    }
+
+    public LocalDateTime getTimestampGreaterThan() {
+        return timestampGreaterThan;
+    }
+
+    public void setTimestampGreaterThan(LocalDateTime timestampGreaterThan) {
+        this.timestampGreaterThan = timestampGreaterThan;
+    }
+
+    public LocalDateTime getTimestampLessThan() {
+        return timestampLessThan;
+    }
+
+    public void setTimestampLessThan(LocalDateTime timestampLessThan) {
+        this.timestampLessThan = timestampLessThan;
+    }
+
+    public boolean getBooleanValue() {
+        return booleanValue;
+    }
+
+    public void setBooleanValue(boolean booleanValue) {
+        this.booleanValue = booleanValue;
+    }
+
+    public Long getCategoryId() {
+        return categoryId;
+    }
+
+    public void setCategoryId(Long categoryId) {
+        this.categoryId = categoryId;
+    }
+
+    public Long getLeftCategorizationId() {
+        return leftCategorizationId;
+    }
+
+    public void setLeftCategorizationId(Long leftCategorizationId) {
+        this.leftCategorizationId = leftCategorizationId;
+    }
+
+    public Long getRightCategorizationId() {
+        return rightCategorizationId;
+    }
+
+    public void setRightCategorizationId(Long rightCategorizationId) {
+        this.rightCategorizationId = rightCategorizationId;
+    }
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/ProcessedTransaction.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/ProcessedTransaction.java
index 008bc47..99cff09 100644
--- a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/ProcessedTransaction.java
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/ProcessedTransaction.java
@@ -1,6 +1,7 @@
 package dev.mvvasilev.finances.entity;
 
 import dev.mvvasilev.common.data.AbstractEntity;
+import dev.mvvasilev.common.data.UserOwned;
 import jakarta.persistence.Entity;
 import jakarta.persistence.Table;
 
@@ -8,7 +9,7 @@ import java.time.LocalDateTime;
 
 @Entity
 @Table(schema = "transactions")
-public class ProcessedTransaction extends AbstractEntity {
+public class ProcessedTransaction extends AbstractEntity implements UserOwned {
 
     private String description;
 
@@ -18,11 +19,9 @@ public class ProcessedTransaction extends AbstractEntity {
 
     private boolean isInflow;
 
-    private Long categoryId;
-
     private LocalDateTime timestamp;
 
-    // private Long transactionMappingId;
+    private Long statementId;
 
     public ProcessedTransaction() {
     }
@@ -51,14 +50,6 @@ public class ProcessedTransaction extends AbstractEntity {
         isInflow = inflow;
     }
 
-    public Long getCategoryId() {
-        return categoryId;
-    }
-
-    public void setCategoryId(Long categoryId) {
-        this.categoryId = categoryId;
-    }
-
     public LocalDateTime getTimestamp() {
         return timestamp;
     }
@@ -75,11 +66,11 @@ public class ProcessedTransaction extends AbstractEntity {
         this.userId = userId;
     }
 
-//    public Long getTransactionMappingId() {
-//        return transactionMappingId;
-//    }
-//
-//    public void setTransactionMappingId(Long transactionMappingId) {
-//        this.transactionMappingId = transactionMappingId;
-//    }
+    public Long getStatementId() {
+        return statementId;
+    }
+
+    public void setStatementId(Long statementId) {
+        this.statementId = statementId;
+    }
 }
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/ProcessedTransactionCategory.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/ProcessedTransactionCategory.java
new file mode 100644
index 0000000..9c7978f
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/ProcessedTransactionCategory.java
@@ -0,0 +1,51 @@
+package dev.mvvasilev.finances.entity;
+
+import jakarta.persistence.*;
+
+@Entity
+@Table(schema = "categories")
+public class ProcessedTransactionCategory {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(columnDefinition = "bigserial")
+    private Long id;
+
+    @Column(nullable = false)
+    private Long processedTransactionId;
+
+    @Column(nullable = false)
+    private Long categoryId;
+
+    public ProcessedTransactionCategory() {
+    }
+
+    public ProcessedTransactionCategory(Long processedTransactionId, Long categoryId) {
+        this.processedTransactionId = processedTransactionId;
+        this.categoryId = categoryId;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getProcessedTransactionId() {
+        return processedTransactionId;
+    }
+
+    public void setProcessedTransactionId(Long processedTransactionId) {
+        this.processedTransactionId = processedTransactionId;
+    }
+
+    public Long getCategoryId() {
+        return categoryId;
+    }
+
+    public void setCategoryId(Long categoryId) {
+        this.categoryId = categoryId;
+    }
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/RawStatement.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/RawStatement.java
index 539914b..eda00ae 100644
--- a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/RawStatement.java
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/RawStatement.java
@@ -1,12 +1,13 @@
 package dev.mvvasilev.finances.entity;
 
 import dev.mvvasilev.common.data.AbstractEntity;
+import dev.mvvasilev.common.data.UserOwned;
 import jakarta.persistence.Entity;
 import jakarta.persistence.Table;
 
 @Entity
 @Table(schema = "transactions")
-public class RawStatement extends AbstractEntity {
+public class RawStatement extends AbstractEntity implements UserOwned {
 
     private Integer userId;
 
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/TransactionCategory.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/TransactionCategory.java
index cca3d61..e586c0b 100644
--- a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/TransactionCategory.java
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/TransactionCategory.java
@@ -1,12 +1,13 @@
 package dev.mvvasilev.finances.entity;
 
 import dev.mvvasilev.common.data.AbstractEntity;
+import dev.mvvasilev.common.data.UserOwned;
 import jakarta.persistence.Entity;
 import jakarta.persistence.Table;
 
 @Entity
 @Table(schema = "categories")
-public class TransactionCategory extends AbstractEntity {
+public class TransactionCategory extends AbstractEntity implements UserOwned {
 
     private Integer userId;
 
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/TransactionMapping.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/TransactionMapping.java
index 5546011..defeb4e 100644
--- a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/TransactionMapping.java
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/entity/TransactionMapping.java
@@ -1,15 +1,37 @@
 package dev.mvvasilev.finances.entity;
 
 import dev.mvvasilev.common.data.AbstractEntity;
+import dev.mvvasilev.common.data.UserOwned;
+import dev.mvvasilev.finances.enums.ProcessedTransactionField;
+import jakarta.persistence.Convert;
 import jakarta.persistence.Entity;
 import jakarta.persistence.Table;
 
-//@Entity
-//@Table(schema = "mappings")
-//public class TransactionMapping extends AbstractEntity {
-//
-//    private Long rawStatementId;
-//
-//
-//
-//}
+@Entity
+@Table(schema = "transactions")
+public class TransactionMapping extends AbstractEntity {
+
+    private Long rawTransactionValueGroupId;
+
+    @Convert(converter = ProcessedTransactionField.JpaConverter.class)
+    private ProcessedTransactionField processedTransactionField;
+
+    public TransactionMapping() {
+    }
+
+    public Long getRawTransactionValueGroupId() {
+        return rawTransactionValueGroupId;
+    }
+
+    public void setRawTransactionValueGroupId(Long rawTransactionValueGroupId) {
+        this.rawTransactionValueGroupId = rawTransactionValueGroupId;
+    }
+
+    public ProcessedTransactionField getProcessedTransactionField() {
+        return processedTransactionField;
+    }
+
+    public void setProcessedTransactionField(ProcessedTransactionField processedTransactionField) {
+        this.processedTransactionField = processedTransactionField;
+    }
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/enums/CategorizationRule.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/enums/CategorizationRule.java
new file mode 100644
index 0000000..9a2c15c
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/enums/CategorizationRule.java
@@ -0,0 +1,42 @@
+package dev.mvvasilev.finances.enums;
+
+import dev.mvvasilev.common.data.AbstractEnumConverter;
+import dev.mvvasilev.common.data.PersistableEnum;
+
+// TODO: Create custom converter for JPA
+public enum CategorizationRule implements PersistableEnum<String> {
+    STRING_REGEX(RawTransactionValueType.STRING),
+    STRING_EQ(RawTransactionValueType.STRING),
+    STRING_CONTAINS(RawTransactionValueType.STRING),
+    NUMERIC_GREATER_THAN(RawTransactionValueType.NUMERIC),
+    NUMERIC_LESS_THAN(RawTransactionValueType.NUMERIC),
+    NUMERIC_EQUALS(RawTransactionValueType.NUMERIC),
+    NUMERIC_BETWEEN(RawTransactionValueType.NUMERIC),
+    TIMESTAMP_GREATER_THAN(RawTransactionValueType.TIMESTAMP),
+    TIMESTAMP_LESS_THAN(RawTransactionValueType.TIMESTAMP),
+    TIMESTAMP_BETWEEN(RawTransactionValueType.TIMESTAMP),
+    BOOLEAN_EQ(RawTransactionValueType.BOOLEAN),
+    AND(null),
+    OR(null),
+    NOT(null);
+
+    final private RawTransactionValueType applicableForType;
+
+    CategorizationRule(RawTransactionValueType applicableForType) {
+        this.applicableForType = applicableForType;
+    }
+
+    public String value() {
+        return name();
+    }
+
+    public RawTransactionValueType applicableForType() {
+        return applicableForType;
+    }
+
+    public static class JpaConverter extends AbstractEnumConverter<CategorizationRule, String> {
+        public JpaConverter() {
+            super(CategorizationRule.class);
+        }
+    }
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/enums/ProcessedTransactionField.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/enums/ProcessedTransactionField.java
new file mode 100644
index 0000000..e20b000
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/enums/ProcessedTransactionField.java
@@ -0,0 +1,33 @@
+package dev.mvvasilev.finances.enums;
+
+import dev.mvvasilev.common.data.AbstractEnumConverter;
+import dev.mvvasilev.common.data.PersistableEnum;
+
+// TODO: Create custom converter for JPA
+public enum ProcessedTransactionField implements PersistableEnum<String> {
+    DESCRIPTION(RawTransactionValueType.STRING),
+    AMOUNT(RawTransactionValueType.NUMERIC),
+    IS_INFLOW(RawTransactionValueType.BOOLEAN),
+    TIMESTAMP(RawTransactionValueType.TIMESTAMP);
+
+    final private RawTransactionValueType type;
+
+    ProcessedTransactionField(RawTransactionValueType type) {
+        this.type = type;
+    }
+
+
+    public String value() {
+        return name();
+    }
+
+    public RawTransactionValueType type() {
+        return type;
+    }
+
+    public static class JpaConverter extends AbstractEnumConverter<ProcessedTransactionField, String> {
+        public JpaConverter() {
+            super(ProcessedTransactionField.class);
+        }
+    }
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/enums/RawTransactionValueType.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/enums/RawTransactionValueType.java
index 0fefb53..1037421 100644
--- a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/enums/RawTransactionValueType.java
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/enums/RawTransactionValueType.java
@@ -1,8 +1,16 @@
 package dev.mvvasilev.finances.enums;
 
-public enum RawTransactionValueType {
+import dev.mvvasilev.common.data.PersistableEnum;
+
+// TODO: Create custom converter for JPA
+public enum RawTransactionValueType implements PersistableEnum<String> {
     STRING,
     NUMERIC,
     TIMESTAMP,
-    BOOLEAN
+    BOOLEAN;
+
+    @Override
+    public String value() {
+        return name();
+    }
 }
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/CategorizationRepository.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/CategorizationRepository.java
new file mode 100644
index 0000000..44de6ca
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/CategorizationRepository.java
@@ -0,0 +1,37 @@
+package dev.mvvasilev.finances.persistence;
+
+import dev.mvvasilev.finances.dtos.CategorizationDTO;
+import dev.mvvasilev.finances.entity.Categorization;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+import org.springframework.stereotype.Repository;
+
+import java.util.Collection;
+
+@Repository
+public interface CategorizationRepository extends JpaRepository<Categorization, Long> {
+
+    // We fetch only the ones with non-null category ids
+    // because ones with null category are used in AND, OR or NOT logical operations
+    @Query(
+            value = """
+                    SELECT cat.*
+                    FROM categories.categorization AS cat
+                    WHERE user_id = :userId AND category_id IS NOT NULL
+                    """,
+            nativeQuery = true
+    )
+    Collection<Categorization> fetchForUser(@Param("userId") int userId);
+
+    // TODO: Use Recursive CTE
+    @Query(
+            value = """
+                    SELECT cat.*
+                    FROM categories.categorization AS cat
+                    WHERE category_id = :categoryId
+                    """,
+            nativeQuery = true
+    )
+    Collection<Categorization> fetchForCategory(@Param("categoryId") Long categoryId);
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/ProcessedTransactionCategoryRepository.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/ProcessedTransactionCategoryRepository.java
new file mode 100644
index 0000000..abfa51b
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/ProcessedTransactionCategoryRepository.java
@@ -0,0 +1,10 @@
+package dev.mvvasilev.finances.persistence;
+
+import dev.mvvasilev.finances.entity.ProcessedTransaction;
+import dev.mvvasilev.finances.entity.ProcessedTransactionCategory;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface ProcessedTransactionCategoryRepository extends JpaRepository<ProcessedTransactionCategory, Long> {
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/ProcessedTransactionRepository.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/ProcessedTransactionRepository.java
new file mode 100644
index 0000000..0192d35
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/ProcessedTransactionRepository.java
@@ -0,0 +1,16 @@
+package dev.mvvasilev.finances.persistence;
+
+import dev.mvvasilev.finances.entity.ProcessedTransaction;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+import org.springframework.stereotype.Repository;
+
+import java.util.Collection;
+
+@Repository
+public interface ProcessedTransactionRepository extends JpaRepository<ProcessedTransaction, Long> {
+
+    @Query(value = "SELECT * FROM transactions.processed_transaction WHERE user_id = :userId", nativeQuery = true)
+    Collection<ProcessedTransaction> fetchForUser(@Param("userId") int userId);
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/RawTransactionValueGroupRepository.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/RawTransactionValueGroupRepository.java
index 6797b60..8df1859 100644
--- a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/RawTransactionValueGroupRepository.java
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/RawTransactionValueGroupRepository.java
@@ -12,16 +12,18 @@ import java.util.Collection;
 @Repository
 public interface RawTransactionValueGroupRepository extends JpaRepository<RawTransactionValueGroup, Long> {
 
-    @Query(value =
-            "SELECT " +
-                    "rtvg.id, " +
-                    "rtvg.name, " +
-                    "rtvg.type " +
-            "FROM transactions.raw_transaction_value_group AS rtvg " +
-            "JOIN transactions.raw_statement AS rs ON rtvg.statement_id = rs.id " +
-            "WHERE rs.user_id = :userId AND rs.id = :statementId",
+    @Query(
+            value = """
+                    SELECT
+                        rtvg.id,
+                        rtvg.name,
+                        rtvg.type
+                    FROM transactions.raw_transaction_value_group AS rtvg
+                    JOIN transactions.raw_statement AS rs ON rtvg.statement_id = rs.id
+                    WHERE rs.id = :statementId
+                    """,
             nativeQuery = true
     )
-    Collection<RawTransactionValueGroupDTO> fetchAllForStatementAndUser(@Param("statementId") Long statementId, @Param("userId") Integer userId);
+    Collection<RawTransactionValueGroupDTO> fetchAllForStatement(@Param("statementId") Long statementId);
 
 }
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/TransactionCategoryRepository.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/TransactionCategoryRepository.java
new file mode 100644
index 0000000..e419987
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/TransactionCategoryRepository.java
@@ -0,0 +1,19 @@
+package dev.mvvasilev.finances.persistence;
+
+import dev.mvvasilev.finances.dtos.CategoryDTO;
+import dev.mvvasilev.finances.entity.TransactionCategory;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+import org.springframework.stereotype.Repository;
+
+import java.util.Collection;
+
+@Repository
+public interface TransactionCategoryRepository extends JpaRepository<TransactionCategory, Long> {
+    @Query(value = "SELECT * FROM categories.transaction_category WHERE user_id = :userId", nativeQuery = true)
+    Collection<TransactionCategory> fetchTransactionCategoriesWithUserId(@Param("userId") int userId);
+
+    @Query(value = "UPDATE categories.transaction_category SET name = :name WHERE id = :categoryId", nativeQuery = true)
+    int updateTransactionCategoryName(@Param("categoryId") Long categoryId, @Param("name") String name);
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/TransactionMappingRepository.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/TransactionMappingRepository.java
new file mode 100644
index 0000000..e1fa0f2
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/TransactionMappingRepository.java
@@ -0,0 +1,26 @@
+package dev.mvvasilev.finances.persistence;
+
+import dev.mvvasilev.finances.entity.TransactionMapping;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+import org.springframework.stereotype.Repository;
+
+import java.util.Collection;
+
+@Repository
+public interface TransactionMappingRepository extends JpaRepository<TransactionMapping, Long> {
+
+    @Query(
+            value = """
+                    SELECT tm.*
+                    FROM transactions.transaction_mappings AS tm
+                    JOIN transactions.raw_transaction_value_group AS rtvg ON rtvg.id = tm.raw_transaction_value_group_id
+                    JOIN transactions.statements AS s ON s.id = rtvg.statement_id
+                    WHERE s.id = :statementId
+                    """,
+            nativeQuery = true
+    )
+    Collection<TransactionMapping> fetchTransactionMappingsWithStatementId(@Param("statementId") Long statementId);
+
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/dtos/RawTransactionDTO.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/dtos/RawTransactionDTO.java
new file mode 100644
index 0000000..d4f0079
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/persistence/dtos/RawTransactionDTO.java
@@ -0,0 +1,4 @@
+package dev.mvvasilev.finances.persistence.dtos;
+
+public interface RawTransactionDTO {
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/services/AuthorizationService.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/services/AuthorizationService.java
new file mode 100644
index 0000000..dd18eaf
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/services/AuthorizationService.java
@@ -0,0 +1,52 @@
+package dev.mvvasilev.finances.services;
+
+import jakarta.persistence.EntityManager;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.stereotype.Service;
+
+@Service("authService")
+public class AuthorizationService {
+
+    final private EntityManager entityManager;
+
+    @Autowired
+    public AuthorizationService(EntityManager entityManager) {
+        this.entityManager = entityManager;
+    }
+
+
+    /**
+     * Check if the user in the {@link SecurityContextHolder} is the owner of the requested resource.
+     * Executes a query on the database, equivalent to the following:
+     * <br>
+     * <pre type="SQL">
+     *     SELECT 1 FROM {user owned entity} WHERE id = :id AND user_id = :userId
+     * </pre>
+     *
+     * @param id the id of the resource to check
+     * @param userOwnedEntity the entity class
+     * @return whether the user is the owner of the resource or not
+     */
+    public boolean isOwner(Long id, Class<?> userOwnedEntity) {
+        var cb = entityManager.getCriteriaBuilder();
+
+        var query = cb.createQuery(Boolean.class);
+        var root = query.from(userOwnedEntity);
+
+        var userId = SecurityContextHolder.getContext().getAuthentication().getName();
+
+        var parsedUserId = Integer.parseInt(userId);
+
+        var finalQuery = query.select(cb.literal(true)).where(
+                cb.and(
+                        cb.equal(root.get("id"), id),
+                        cb.equal(root.get("userId"), parsedUserId)
+                )
+        );
+
+        // If no results were returned, then the user was not the owner of the resource
+        return !entityManager.createQuery(finalQuery).setMaxResults(1).getResultList().isEmpty();
+    }
+
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/services/CategoryService.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/services/CategoryService.java
new file mode 100644
index 0000000..fd473a4
--- /dev/null
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/services/CategoryService.java
@@ -0,0 +1,276 @@
+package dev.mvvasilev.finances.services;
+
+import dev.mvvasilev.common.exceptions.CommonFinancesException;
+import dev.mvvasilev.finances.dtos.*;
+import dev.mvvasilev.finances.entity.Categorization;
+import dev.mvvasilev.finances.entity.ProcessedTransaction;
+import dev.mvvasilev.finances.entity.ProcessedTransactionCategory;
+import dev.mvvasilev.finances.entity.TransactionCategory;
+import dev.mvvasilev.finances.persistence.CategorizationRepository;
+import dev.mvvasilev.finances.persistence.ProcessedTransactionCategoryRepository;
+import dev.mvvasilev.finances.persistence.ProcessedTransactionRepository;
+import dev.mvvasilev.finances.persistence.TransactionCategoryRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.time.LocalDateTime;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Collectors;
+
+@Service
+public class CategoryService {
+
+    final private TransactionCategoryRepository transactionCategoryRepository;
+
+    final private CategorizationRepository categorizationRepository;
+
+    final private ProcessedTransactionRepository processedTransactionRepository;
+
+    final private ProcessedTransactionCategoryRepository processedTransactionCategoryRepository;
+
+    @Autowired
+    public CategoryService(
+            TransactionCategoryRepository transactionCategoryRepository,
+            CategorizationRepository categorizationRepository,
+            ProcessedTransactionRepository processedTransactionRepository,
+            ProcessedTransactionCategoryRepository processedTransactionCategoryRepository
+    ) {
+        this.transactionCategoryRepository = transactionCategoryRepository;
+        this.categorizationRepository = categorizationRepository;
+        this.processedTransactionRepository = processedTransactionRepository;
+        this.processedTransactionCategoryRepository = processedTransactionCategoryRepository;
+    }
+
+    public Long createForUser(CreateCategoryDTO dto, int userId) {
+        var transactionCategory = new TransactionCategory();
+
+        transactionCategory.setName(dto.name());
+        transactionCategory.setUserId(userId);
+
+        transactionCategory = transactionCategoryRepository.saveAndFlush(transactionCategory);
+
+        return transactionCategory.getId();
+    }
+
+    public Collection<CategoryDTO> listForUser(int userId) {
+        return transactionCategoryRepository.fetchTransactionCategoriesWithUserId(userId)
+                .stream()
+                .map(entity -> new CategoryDTO(entity.getId(), entity.getName()))
+                .collect(Collectors.toList());
+    }
+
+    public int update(Long categoryId, UpdateCategoryDTO dto) {
+        return transactionCategoryRepository.updateTransactionCategoryName(
+                categoryId,
+                dto.name()
+        );
+    }
+
+    public int delete(Long categoryId) {
+        transactionCategoryRepository.deleteById(categoryId);
+        return 1; // Affected rows. TODO: Actually fetch from database
+    }
+
+    public void categorizeForUser(int userId) {
+        final var categorizations = categorizationRepository.fetchForUser(userId);
+        final var transactions = processedTransactionRepository.fetchForUser(userId);
+
+        // Run all the categorization rules async
+        final var futures = categorizations.stream()
+                .map(c -> CompletableFuture.supplyAsync(() ->
+                        transactions.stream()
+                                .map((transaction) -> categorizeTransaction(categorizations, c, transaction))
+                                .filter(Optional::isPresent)
+                                .map(Optional::get)
+                                .toList())
+                )
+                .toArray(length -> (CompletableFuture<List<ProcessedTransactionCategory>>[]) new CompletableFuture[length]);
+
+        // Run them all in parallel
+        final var categories = CompletableFuture.allOf(futures).thenApply((v) ->
+                Arrays.stream(futures)
+                        .flatMap(future -> future.join().stream())
+                        .toList()
+        ).join();
+
+        processedTransactionCategoryRepository.saveAllAndFlush(categories);
+    }
+
+    private Optional<ProcessedTransactionCategory> categorizeTransaction(final Collection<Categorization> allCategorizations, Categorization categorization, ProcessedTransaction processedTransaction) {
+        if (matchesRule(allCategorizations, categorization, processedTransaction)) {
+            return Optional.of(new ProcessedTransactionCategory(processedTransaction.getId(), categorization.getCategoryId()));
+        } else {
+            return Optional.empty();
+        }
+    }
+
+    private boolean matchesRule(final Collection<Categorization> allCategorizations, final Categorization categorization, final ProcessedTransaction processedTransaction) {
+        return switch (categorization.getCategorizationRule()) {
+            // string operations
+            case STRING_REGEX, STRING_EQ, STRING_CONTAINS -> {
+                final String fieldValue = fetchTransactionStringValue(categorization, processedTransaction);
+
+                yield switch (categorization.getCategorizationRule()) {
+                    case STRING_EQ -> fieldValue.equalsIgnoreCase(categorization.getStringValue());
+                    case STRING_REGEX -> fieldValue.matches(categorization.getStringValue());
+                    case STRING_CONTAINS -> fieldValue.contains(categorization.getStringValue());
+                    default -> throw new CommonFinancesException("Unsupported string rule: %s", categorization.getCategorizationRule());
+                };
+            }
+            // numeric operations
+            case NUMERIC_GREATER_THAN, NUMERIC_LESS_THAN, NUMERIC_EQUALS, NUMERIC_BETWEEN -> {
+                final double fieldValue = fetchTransactionNumericValue(categorization, processedTransaction);
+
+                yield switch (categorization.getCategorizationRule()) {
+                    case NUMERIC_GREATER_THAN -> fieldValue > categorization.getNumericGreaterThan();
+                    case NUMERIC_LESS_THAN -> fieldValue < categorization.getNumericLessThan();
+                    case NUMERIC_EQUALS -> fieldValue == categorization.getNumericValue();
+                    case NUMERIC_BETWEEN -> fieldValue > categorization.getNumericGreaterThan() && fieldValue < categorization.getNumericLessThan();
+                    default -> throw new CommonFinancesException("Unsupported numeric rule: %s", categorization.getCategorizationRule());
+                };
+            }
+            // datetime/timestamp operations
+            case TIMESTAMP_GREATER_THAN, TIMESTAMP_LESS_THAN, TIMESTAMP_BETWEEN -> {
+                final LocalDateTime fieldValue = fetchTransactionTimestampValue(categorization, processedTransaction);
+
+                yield switch (categorization.getCategorizationRule()) {
+                    case TIMESTAMP_GREATER_THAN -> fieldValue.isBefore(categorization.getTimestampGreaterThan());
+                    case TIMESTAMP_LESS_THAN -> fieldValue.isAfter(categorization.getTimestampLessThan());
+                    case TIMESTAMP_BETWEEN -> fieldValue.isBefore(categorization.getTimestampGreaterThan()) && fieldValue.isAfter(categorization.getTimestampLessThan());
+                    default -> throw new CommonFinancesException("Unsupported timestamp rule: %s", categorization.getCategorizationRule());
+                };
+            }
+            // boolean operations
+            case BOOLEAN_EQ -> {
+                final boolean equalsValue = categorization.getBooleanValue();
+
+                boolean fieldValue = fetchTransactionBooleanValue(categorization, processedTransaction);
+
+                yield equalsValue == fieldValue;
+            }
+            // logical operations
+            case OR, AND, NOT -> {
+                var leftId = categorization.getLeftCategorizationId();
+                var rightId = categorization.getRightCategorizationId();
+
+                final var left = allCategorizations.stream()
+                        .filter(c -> c.getId() == leftId)
+                        .findFirst();
+
+                final var right = allCategorizations.stream()
+                        .filter(c -> c.getId() == rightId)
+                        .findFirst();
+
+                yield switch (categorization.getCategorizationRule()) {
+                    case AND -> {
+                        if (right.isEmpty()) {
+                            throw new CommonFinancesException("Invalid categorization: right does not exist");
+                        }
+
+                        if (left.isEmpty()) {
+                            throw new CommonFinancesException("Invalid categorization: left does not exist");
+                        }
+
+                        yield matchesRule(allCategorizations, left.get(), processedTransaction) && matchesRule(allCategorizations, right.get(), processedTransaction);
+                    }
+                    case OR -> {
+                        if (right.isEmpty()) {
+                            throw new CommonFinancesException("Invalid categorization: right does not exist");
+                        }
+
+                        if (left.isEmpty()) {
+                            throw new CommonFinancesException("Invalid categorization: left does not exist");
+                        }
+
+                        yield matchesRule(allCategorizations, left.get(), processedTransaction) || matchesRule(allCategorizations, right.get(), processedTransaction);
+                    }
+                    case NOT -> {
+                        if (right.isEmpty()) {
+                            throw new CommonFinancesException("Invalid categorization: right does not exist");
+                        }
+
+                        yield !matchesRule(allCategorizations, right.get(), processedTransaction);
+                    }
+                    default -> throw new CommonFinancesException("Invalid logical operation: %s", categorization.getCategorizationRule());
+                };
+            }
+        };
+    }
+
+    private String fetchTransactionStringValue(Categorization categorization, ProcessedTransaction processedTransaction) {
+        return switch (categorization.getRuleBasedOn()) {
+            case DESCRIPTION -> processedTransaction.getDescription();
+            case AMOUNT, IS_INFLOW, TIMESTAMP -> throw invalidCategorizationRule(categorization);
+        };
+    }
+
+    private double fetchTransactionNumericValue(Categorization categorization, ProcessedTransaction processedTransaction) {
+        return switch (categorization.getRuleBasedOn()) {
+            case AMOUNT -> processedTransaction.getAmount();
+            case DESCRIPTION, IS_INFLOW, TIMESTAMP -> throw invalidCategorizationRule(categorization);
+        };
+    }
+
+    private LocalDateTime fetchTransactionTimestampValue(Categorization categorization, ProcessedTransaction processedTransaction) {
+        return switch (categorization.getRuleBasedOn()) {
+            case TIMESTAMP -> processedTransaction.getTimestamp();
+            case DESCRIPTION, IS_INFLOW, AMOUNT -> throw invalidCategorizationRule(categorization);
+        };
+    }
+
+    private boolean fetchTransactionBooleanValue(Categorization categorization, ProcessedTransaction processedTransaction) {
+        return switch (categorization.getRuleBasedOn()) {
+            case IS_INFLOW -> processedTransaction.isInflow();
+            case DESCRIPTION, TIMESTAMP, AMOUNT -> throw invalidCategorizationRule(categorization);
+        };
+    }
+
+    private CommonFinancesException invalidCategorizationRule(Categorization categorization) {
+        throw new CommonFinancesException(
+                "Invalid categorization rule: field %s is of type %s, while the rule is applicable only for type %s",
+                categorization.getRuleBasedOn(),
+                categorization.getRuleBasedOn().type(),
+                categorization.getCategorizationRule().applicableForType()
+        );
+    }
+
+    public Collection<CategorizationDTO> fetchCategorizationRules(Long categoryId) {
+        return categorizationRepository.fetchForCategory(categoryId).stream()
+                .map(entity -> {
+                    // TODO: Recursion
+                })
+                .toList();
+    }
+
+    public Long createCategorizationRule(Long categoryId, Collection<CreateCategorizationDTO> dto) {
+        // TODO: Clear previous rules for category and replace with new ones
+
+//        final var categorization = new Categorization();
+//
+//        categorization.setCategorizationRule(dto.rule());
+//        categorization.setCategoryId(categoryId);
+//        categorization.setStringValue(dto.stringValue());
+//        categorization.setNumericGreaterThan(dto.numericGreaterThan());
+//        categorization.setNumericLessThan(dto.numericLessThan());
+//        categorization.setNumericValue(dto.numericValue());
+//        categorization.setTimestampGreaterThan(dto.timestampGreaterThan());
+//        categorization.setTimestampLessThan(dto.timestampLessThan());
+//        categorization.setBooleanValue(dto.booleanValue());
+//
+//        if (dto.left() != null) {
+//            final var leftCat = createCategorizationRule(null, dto.left());
+//            categorization.setLeftCategorizationId(leftCat);
+//        }
+//
+//        if (dto.right() != null) {
+//            final var rightCat = createCategorizationRule(null, dto.right());
+//            categorization.setRightCategorizationId(rightCat);
+//        }
+//
+//        return categorizationRepository.save(categorization).getId();
+    }
+}
diff --git a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/services/StatementsService.java b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/services/StatementsService.java
index 3c976e9..649942f 100644
--- a/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/services/StatementsService.java
+++ b/PersonalFinancesService/src/main/java/dev/mvvasilev/finances/services/StatementsService.java
@@ -1,20 +1,26 @@
 package dev.mvvasilev.finances.services;
 
+import dev.mvvasilev.common.web.CrudResponseDTO;
+import dev.mvvasilev.finances.dtos.CreateTransactionMappingDTO;
+import dev.mvvasilev.finances.dtos.TransactionMappingDTO;
 import dev.mvvasilev.finances.dtos.TransactionValueGroupDTO;
 import dev.mvvasilev.finances.dtos.UploadedStatementDTO;
 import dev.mvvasilev.finances.entity.RawStatement;
 import dev.mvvasilev.finances.entity.RawTransactionValue;
 import dev.mvvasilev.finances.entity.RawTransactionValueGroup;
+import dev.mvvasilev.finances.entity.TransactionMapping;
+import dev.mvvasilev.finances.enums.ProcessedTransactionField;
 import dev.mvvasilev.finances.enums.RawTransactionValueType;
 import dev.mvvasilev.finances.persistence.RawStatementRepository;
 import dev.mvvasilev.finances.persistence.RawTransactionValueGroupRepository;
 import dev.mvvasilev.finances.persistence.RawTransactionValueRepository;
-import jakarta.transaction.Transactional;
+import dev.mvvasilev.finances.persistence.TransactionMappingRepository;
 import org.apache.poi.ss.usermodel.CellType;
 import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.WorkbookFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -24,14 +30,10 @@ import java.time.format.DateTimeFormatterBuilder;
 import java.time.format.DateTimeParseException;
 import java.time.format.ResolverStyle;
 import java.time.temporal.ChronoField;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.List;
-import java.util.Optional;
+import java.util.*;
 import java.util.stream.Collectors;
 
 @Service
-@Transactional
 public class StatementsService {
 
     private static final DateTimeFormatter DATE_FORMAT = new DateTimeFormatterBuilder()
@@ -42,21 +44,25 @@ public class StatementsService {
             .toFormatter()
             .withResolverStyle(ResolverStyle.LENIENT);
 
-    private RawStatementRepository rawStatementRepository;
+    private final RawStatementRepository rawStatementRepository;
 
-    private RawTransactionValueGroupRepository rawTransactionValueGroupRepository;
+    private final RawTransactionValueGroupRepository rawTransactionValueGroupRepository;
 
-    private RawTransactionValueRepository rawTransactionValueRepository;
+    private final RawTransactionValueRepository rawTransactionValueRepository;
+
+    private final TransactionMappingRepository transactionMappingRepository;
 
     @Autowired
-    public StatementsService(RawStatementRepository rawStatementRepository, RawTransactionValueGroupRepository rawTransactionValueGroupRepository, RawTransactionValueRepository rawTransactionValueRepository) {
+    public StatementsService(RawStatementRepository rawStatementRepository, RawTransactionValueGroupRepository rawTransactionValueGroupRepository, RawTransactionValueRepository rawTransactionValueRepository, TransactionMappingRepository transactionMappingRepository) {
         this.rawStatementRepository = rawStatementRepository;
         this.rawTransactionValueGroupRepository = rawTransactionValueGroupRepository;
         this.rawTransactionValueRepository = rawTransactionValueRepository;
+        this.transactionMappingRepository = transactionMappingRepository;
     }
 
 
-    public void uploadStatementFromExcelSheetForUser(String fileName, String mimeType, InputStream workbookInputStream, int userId) throws IOException {
+    @Transactional
+    public void uploadStatementFromExcelSheetForUser(final String fileName, final String mimeType, final InputStream workbookInputStream, final int userId) throws IOException {
 
         var workbook = WorkbookFactory.create(workbookInputStream);
 
@@ -121,9 +127,12 @@ public class StatementsService {
 
                 switch (group.getType()) {
                     case STRING -> value.setStringValue(firstWorksheet.getRow(y).getCell(column).getStringCellValue());
-                    case NUMERIC -> value.setNumericValue(firstWorksheet.getRow(y).getCell(column).getNumericCellValue());
-                    case TIMESTAMP -> value.setTimestampValue(LocalDateTime.parse(firstWorksheet.getRow(y).getCell(column).getStringCellValue().trim(), DATE_FORMAT));
-                    case BOOLEAN -> value.setBooleanValue(firstWorksheet.getRow(y).getCell(column).getBooleanCellValue());
+                    case NUMERIC ->
+                            value.setNumericValue(firstWorksheet.getRow(y).getCell(column).getNumericCellValue());
+                    case TIMESTAMP ->
+                            value.setTimestampValue(LocalDateTime.parse(firstWorksheet.getRow(y).getCell(column).getStringCellValue().trim(), DATE_FORMAT));
+                    case BOOLEAN ->
+                            value.setBooleanValue(firstWorksheet.getRow(y).getCell(column).getBooleanCellValue());
                 }
 
                 valueList.add(value);
@@ -135,7 +144,7 @@ public class StatementsService {
         }
     }
 
-    private Optional<RawTransactionValueType> determineGroupType(Sheet worksheet, int rowIndex, int columnIndex) {
+    private Optional<RawTransactionValueType> determineGroupType(final Sheet worksheet, final int rowIndex, final int columnIndex) {
         var cell = worksheet.getRow(rowIndex).getCell(columnIndex);
 
         if (cell == null || cell.getCellType() == CellType.BLANK) {
@@ -168,22 +177,62 @@ public class StatementsService {
         return true;
     }
 
-    public Collection<UploadedStatementDTO> fetchStatementsForUser(int userId) {
+    public Collection<UploadedStatementDTO> fetchStatementsForUser(final int userId) {
         return rawStatementRepository.fetchAllForUser(userId)
                 .stream()
                 .map(dto -> new UploadedStatementDTO(dto.getId(), dto.getName(), dto.getTimeCreated()))
                 .collect(Collectors.toList());
     }
 
-    public Collection<TransactionValueGroupDTO> fetchTransactionValueGroupsForUserStatement(Long statementId, int userId) {
-        return rawTransactionValueGroupRepository.fetchAllForStatementAndUser(statementId, userId)
+    public Collection<TransactionValueGroupDTO> fetchTransactionValueGroupsForUserStatement(final Long statementId) {
+        return rawTransactionValueGroupRepository.fetchAllForStatement(statementId)
                 .stream()
                 .map(dto -> new TransactionValueGroupDTO(dto.getId(), dto.getName(), RawTransactionValueType.values()[dto.getType()]))
                 .collect(Collectors.toList());
     }
 
-    public void deleteStatement(Long statementId, int userId) {
+    @Transactional
+    public void deleteStatement(final Long statementId) {
         rawStatementRepository.deleteById(statementId);
         rawStatementRepository.flush();
     }
+
+    public Collection<TransactionMappingDTO> fetchMappingsForStatement(Long statementId) {
+        return transactionMappingRepository.fetchTransactionMappingsWithStatementId(statementId)
+                .stream()
+                .map(entity -> new TransactionMappingDTO(
+                                entity.getId(),
+                                entity.getRawTransactionValueGroupId(),
+                                entity.getProcessedTransactionField()
+                        )
+                )
+                .toList();
+    }
+
+    public Collection<CrudResponseDTO> createTransactionMappingsForStatement(Long statementId, Collection<CreateTransactionMappingDTO> dtos) {
+        return transactionMappingRepository.saveAllAndFlush(
+                    dtos.stream()
+                        .map(dto -> {
+                            final var mapping = new TransactionMapping();
+
+                            mapping.setRawTransactionValueGroupId(dto.rawTransactionValueGroupId());
+                            mapping.setProcessedTransactionField(dto.field());
+
+                            return mapping;
+                        })
+                        .toList()
+                )
+                .stream()
+                .map(entity -> new CrudResponseDTO(entity.getId(), 1))
+                .toList();
+
+    }
+
+    public void processStatement(Long statementId) {
+        final var mappings = transactionMappingRepository.fetchTransactionMappingsWithStatementId(statementId);
+        final var mappingByField = new HashMap<ProcessedTransactionField, Long>();
+
+        mappings.forEach(m -> mappingByField.put(m.getProcessedTransactionField(), m.getRawTransactionValueGroupId()));
+
+    }
 }
diff --git a/PersonalFinancesService/src/main/resources/db/migration/V1.10__CreateProcessedTransactionCategory.sql b/PersonalFinancesService/src/main/resources/db/migration/V1.10__CreateProcessedTransactionCategory.sql
new file mode 100644
index 0000000..92ac7c8
--- /dev/null
+++ b/PersonalFinancesService/src/main/resources/db/migration/V1.10__CreateProcessedTransactionCategory.sql
@@ -0,0 +1,8 @@
+CREATE TABLE IF NOT EXISTS categories.processed_transaction_category (
+    id BIGSERIAL,
+    processed_transaction_id BIGINT,
+    category_id BIGINT,
+    CONSTRAINT PK_processed_transaction_category PRIMARY KEY (id),
+    CONSTRAINT FK_processed_transaction_category_category FOREIGN KEY (category_id) REFERENCES categories.category(id) ON DELETE CASCADE,
+    CONSTRAINT FK_processed_transaction_category_processed_transaction FOREIGN KEY (processed_transaction_id) REFERENCES transactions.processed_transaction(id) ON DELETE CASCADE
+);
\ No newline at end of file
diff --git a/PersonalFinancesService/src/main/resources/db/migration/V1.11__CreateTransactionMapping.sql b/PersonalFinancesService/src/main/resources/db/migration/V1.11__CreateTransactionMapping.sql
new file mode 100644
index 0000000..38519d2
--- /dev/null
+++ b/PersonalFinancesService/src/main/resources/db/migration/V1.11__CreateTransactionMapping.sql
@@ -0,0 +1,9 @@
+CREATE TABLE IF NOT EXISTS trasactions.transaction_mapping (
+    id BIGSERIAL,
+    time_created TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL,
+    time_last_modified TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL,
+    raw_transaction_value_group_id BIGINT,
+    processed_transaction_field VARCHAR(255),
+    CONSTRAINT PK_transaction_mapping PRIMARY KEY (id),
+    CONSTRAINT FK_transaction_mapping_raw_transaction_value_group FOREIGN KEY(raw_transaction_value_group_id) REFERENCES transactions.raw_transaction_value_group(id) ON DELETE CASCADE
+);
\ No newline at end of file
diff --git a/PersonalFinancesService/src/main/resources/db/migration/V1.12__CreateCategorization.sql b/PersonalFinancesService/src/main/resources/db/migration/V1.12__CreateCategorization.sql
new file mode 100644
index 0000000..5c530b4
--- /dev/null
+++ b/PersonalFinancesService/src/main/resources/db/migration/V1.12__CreateCategorization.sql
@@ -0,0 +1,22 @@
+CREATE TABLE IF NOT EXISTS categories.categorization (
+    id BIGSERIAL,
+    time_created TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL,
+    time_last_modified TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL,
+    user_id INTEGER NOT NULL,
+    rule_based_on VARCHAR(255),
+    categorization_rule VARCHAR(255),
+    string_value VARCHAR(1024),
+    numeric_greater_than INTEGER,
+    numeric_less_than INTEGER,
+    numeric_value INTEGER,
+    timestamp_greater_than TIMESTAMP,
+    timestamp_less_than TIMESTAMP,
+    boolean_value BOOLEAN,
+    category_id BIGINT NULL,
+    left_categorization_id BIGINT,
+    right_categorization_id BIGINT,
+    CONSTRAINT PK_categorization PRIMARY KEY (id),
+    CONSTRAINT FK_categorization_category FOREIGN KEY (category_id) REFERENCES categories.category(id),
+    CONSTRAINT FK_categorization_categorization_left FOREIGN KEY (left_categorization_id) REFERENCES categories.categorization(left_categorization_id) ON DELETE CASCADE,
+    CONSTRAINT FK_categorization_categorization_right FOREIGN KEY (right_categorization_id) REFERENCES categories.categorization(right_categorization_id) ON DELETE CASCADE
+);
\ No newline at end of file
diff --git a/PersonalFinancesService/src/main/resources/db/migration/V1.1__AddUserIdToRawStatement.sql b/PersonalFinancesService/src/main/resources/db/migration/V1.1__AddUserIdToRawStatement.sql
index 58ecdce..e93f203 100644
--- a/PersonalFinancesService/src/main/resources/db/migration/V1.1__AddUserIdToRawStatement.sql
+++ b/PersonalFinancesService/src/main/resources/db/migration/V1.1__AddUserIdToRawStatement.sql
@@ -1 +1 @@
-ALTER TABLE transactions.raw_statement ADD user_id INTEGER NOT NULL;
\ No newline at end of file
+ALTER TABLE transactions.raw_statement ADD COLUMN IF NOT EXISTS user_id INTEGER NOT NULL;
\ No newline at end of file
diff --git a/PersonalFinancesService/src/main/resources/db/migration/V1.2__AddBooleanValueToRawTransactionValue.sql b/PersonalFinancesService/src/main/resources/db/migration/V1.2__AddBooleanValueToRawTransactionValue.sql
index 14f479c..83e6f7d 100644
--- a/PersonalFinancesService/src/main/resources/db/migration/V1.2__AddBooleanValueToRawTransactionValue.sql
+++ b/PersonalFinancesService/src/main/resources/db/migration/V1.2__AddBooleanValueToRawTransactionValue.sql
@@ -1 +1 @@
-ALTER TABLE transactions.raw_transaction_value ADD boolean_value BOOLEAN;
\ No newline at end of file
+ALTER TABLE transactions.raw_transaction_value ADD COLUMN IF NOT EXISTS boolean_value BOOLEAN;
\ No newline at end of file
diff --git a/PersonalFinancesService/src/main/resources/db/migration/V1.5__AddUserIdToTransactionCategory.sql b/PersonalFinancesService/src/main/resources/db/migration/V1.5__AddUserIdToTransactionCategory.sql
index 34e81d3..0a6cfbd 100644
--- a/PersonalFinancesService/src/main/resources/db/migration/V1.5__AddUserIdToTransactionCategory.sql
+++ b/PersonalFinancesService/src/main/resources/db/migration/V1.5__AddUserIdToTransactionCategory.sql
@@ -1,3 +1,3 @@
-ALTER TABLE transactions.processed_transaction ADD user_id INTEGER;
+ALTER TABLE transactions.processed_transaction ADD COLUMN IF NOT EXISTS user_id INTEGER;
 
-ALTER TABLE categories.transaction_category ADD user_id INTEGER;
\ No newline at end of file
+ALTER TABLE categories.transaction_category ADD COLUMN IF NOT EXISTS user_id INTEGER;
\ No newline at end of file
diff --git a/PersonalFinancesService/src/main/resources/db/migration/V1.6__AddRowIndexToRawTransactionValue.sql b/PersonalFinancesService/src/main/resources/db/migration/V1.6__AddRowIndexToRawTransactionValue.sql
index 8526e97..5c6594f 100644
--- a/PersonalFinancesService/src/main/resources/db/migration/V1.6__AddRowIndexToRawTransactionValue.sql
+++ b/PersonalFinancesService/src/main/resources/db/migration/V1.6__AddRowIndexToRawTransactionValue.sql
@@ -1 +1 @@
-ALTER TABLE transactions.raw_transaction_value ADD row_index INTEGER NOT NULL;
\ No newline at end of file
+ALTER TABLE transactions.raw_transaction_value ADD COLUMN IF NOT EXISTS row_index INTEGER NOT NULL;
\ No newline at end of file
diff --git a/PersonalFinancesService/src/main/resources/db/migration/V1.7__AddNameToRawStatement.sql b/PersonalFinancesService/src/main/resources/db/migration/V1.7__AddNameToRawStatement.sql
index 9fcb1c0..2bea7ce 100644
--- a/PersonalFinancesService/src/main/resources/db/migration/V1.7__AddNameToRawStatement.sql
+++ b/PersonalFinancesService/src/main/resources/db/migration/V1.7__AddNameToRawStatement.sql
@@ -1 +1 @@
-ALTER TABLE transactions.raw_statement ADD name VARCHAR(255);
\ No newline at end of file
+ALTER TABLE transactions.raw_statement ADD COLUMN IF NOT EXISTS name VARCHAR(255);
\ No newline at end of file
diff --git a/PersonalFinancesService/src/main/resources/db/migration/V1.9__AlterProcessedTransaction_RemoveCategoryId.sql b/PersonalFinancesService/src/main/resources/db/migration/V1.9__AlterProcessedTransaction_RemoveCategoryId.sql
new file mode 100644
index 0000000..8713414
--- /dev/null
+++ b/PersonalFinancesService/src/main/resources/db/migration/V1.9__AlterProcessedTransaction_RemoveCategoryId.sql
@@ -0,0 +1,2 @@
+ALTER TABLE transactions.processed_transaction
+DROP COLUMN IF EXISTS category_id;
\ No newline at end of file