diff --git a/packages/server/src/modules/Items/Item.controller.ts b/packages/server/src/modules/Items/Item.controller.ts
index 0bf559cd6..5f174f766 100644
--- a/packages/server/src/modules/Items/Item.controller.ts
+++ b/packages/server/src/modules/Items/Item.controller.ts
@@ -34,6 +34,7 @@ import {
   BulkDeleteItemsDto,
   ValidateBulkDeleteItemsResponseDto,
 } from './dtos/BulkDeleteItems.dto';
+import { ItemApiErrorResponseDto } from './dtos/ItemErrorResponse.dto';
 
 @Controller('/items')
 @ApiTags('Items')
@@ -45,6 +46,7 @@ import {
 @ApiExtraModels(ItemEstimatesResponseDto)
 @ApiExtraModels(ItemReceiptsResponseDto)
 @ApiExtraModels(ValidateBulkDeleteItemsResponseDto)
+@ApiExtraModels(ItemApiErrorResponseDto)
 @ApiCommonHeaders()
 export class ItemsController extends TenantController {
   constructor(private readonly itemsApplication: ItemsApplicationService) {
@@ -147,6 +149,13 @@ export class ItemsController extends TenantController {
     status: 200,
     description: 'The item has been successfully updated.',
   })
+  @ApiResponse({
+    status: 400,
+    description: 'Validation error. Possible error types: ITEM_NAME_EXISTS, INVENTORY_ACCOUNT_CANNOT_MODIFIED, TYPE_CANNOT_CHANGE_WITH_ITEM_HAS_TRANSACTIONS, etc.',
+    schema: {
+      $ref: getSchemaPath(ItemApiErrorResponseDto),
+    },
+  })
   @ApiResponse({ status: 404, description: 'The item not found.' })
   @ApiParam({
     name: 'id',
@@ -204,6 +213,13 @@ export class ItemsController extends TenantController {
     status: 200,
     description: 'The item has been successfully created.',
   })
+  @ApiResponse({
+    status: 400,
+    description: 'Validation error. Possible error types: ITEM_NAME_EXISTS, ITEM_CATEOGRY_NOT_FOUND, COST_ACCOUNT_NOT_COGS, SELL_ACCOUNT_NOT_INCOME, INVENTORY_ACCOUNT_NOT_INVENTORY, INCOME_ACCOUNT_REQUIRED_WITH_SELLABLE_ITEM, COST_ACCOUNT_REQUIRED_WITH_PURCHASABLE_ITEM, etc.',
+    schema: {
+      $ref: getSchemaPath(ItemApiErrorResponseDto),
+    },
+  })
   // @UsePipes(new ZodValidationPipe(createItemSchema))
   async createItem(
     @Body() createItemDto: CreateItemDto,
@@ -219,6 +235,13 @@ export class ItemsController extends TenantController {
     status: 200,
     description: 'The item has been successfully deleted.',
   })
+  @ApiResponse({
+    status: 400,
+    description: 'Cannot delete item. Possible error types: ITEM_HAS_ASSOCIATED_TRANSACTINS, ITEM_HAS_ASSOCIATED_INVENTORY_ADJUSTMENT, etc.',
+    schema: {
+      $ref: getSchemaPath(ItemApiErrorResponseDto),
+    },
+  })
   @ApiResponse({ status: 404, description: 'The item not found.' })
   @ApiParam({
     name: 'id',
diff --git a/packages/server/src/modules/Items/dtos/ItemErrorResponse.dto.ts b/packages/server/src/modules/Items/dtos/ItemErrorResponse.dto.ts
new file mode 100644
index 000000000..69ed391d7
--- /dev/null
+++ b/packages/server/src/modules/Items/dtos/ItemErrorResponse.dto.ts
@@ -0,0 +1,112 @@
+import { ApiProperty } from '@nestjs/swagger';
+
+/**
+ * Item API Error Types
+ * These error types are returned when item operations fail validation
+ */
+export enum ItemErrorType {
+  /** Item name already exists in the system */
+  ItemNameExists = 'ITEM_NAME_EXISTS',
+  
+  /** Item category was not found */
+  ItemCategoryNotFound = 'ITEM_CATEOGRY_NOT_FOUND',
+  
+  /** Cost account is not a Cost of Goods Sold account */
+  CostAccountNotCogs = 'COST_ACCOUNT_NOT_COGS',
+  
+  /** Cost account was not found */
+  CostAccountNotFound = 'COST_ACCOUNT_NOT_FOUMD',
+  
+  /** Sell account was not found */
+  SellAccountNotFound = 'SELL_ACCOUNT_NOT_FOUND',
+  
+  /** Sell account is not an income account */
+  SellAccountNotIncome = 'SELL_ACCOUNT_NOT_INCOME',
+  
+  /** Inventory account was not found */
+  InventoryAccountNotFound = 'INVENTORY_ACCOUNT_NOT_FOUND',
+  
+  /** Account is not an inventory type account */
+  InventoryAccountNotInventory = 'INVENTORY_ACCOUNT_NOT_INVENTORY',
+  
+  /** Multiple items have associated transactions */
+  ItemsHaveAssociatedTransactions = 'ITEMS_HAVE_ASSOCIATED_TRANSACTIONS',
+  
+  /** Item has associated transactions (singular) */
+  ItemHasAssociatedTransactions = 'ITEM_HAS_ASSOCIATED_TRANSACTINS',
+  
+  /** Item has associated inventory adjustments */
+  ItemHasAssociatedInventoryAdjustment = 'ITEM_HAS_ASSOCIATED_INVENTORY_ADJUSTMENT',
+  
+  /** Cannot change item type to inventory */
+  ItemCannotChangeInventoryType = 'ITEM_CANNOT_CHANGE_INVENTORY_TYPE',
+  
+  /** Cannot change type when item has transactions */
+  TypeCannotChangeWithItemHasTransactions = 'TYPE_CANNOT_CHANGE_WITH_ITEM_HAS_TRANSACTIONS',
+  
+  /** Inventory account cannot be modified */
+  InventoryAccountCannotModified = 'INVENTORY_ACCOUNT_CANNOT_MODIFIED',
+  
+  /** Purchase tax rate was not found */
+  PurchaseTaxRateNotFound = 'PURCHASE_TAX_RATE_NOT_FOUND',
+  
+  /** Sell tax rate was not found */
+  SellTaxRateNotFound = 'SELL_TAX_RATE_NOT_FOUND',
+  
+  /** Income account is required for sellable items */
+  IncomeAccountRequiredWithSellableItem = 'INCOME_ACCOUNT_REQUIRED_WITH_SELLABLE_ITEM',
+  
+  /** Cost account is required for purchasable items */
+  CostAccountRequiredWithPurchasableItem = 'COST_ACCOUNT_REQUIRED_WITH_PURCHASABLE_ITEM',
+  
+  /** Item not found */
+  NotFound = 'NOT_FOUND',
+  
+  /** Items not found */
+  ItemsNotFound = 'ITEMS_NOT_FOUND',
+}
+
+/**
+ * Item API Error Response
+ * Returned when an item operation fails
+ */
+export class ItemErrorResponseDto {
+  @ApiProperty({
+    description: 'HTTP status code',
+    example: 400,
+  })
+  statusCode: number;
+
+  @ApiProperty({
+    description: 'Error type identifier',
+    enum: ItemErrorType,
+    example: ItemErrorType.ItemNameExists,
+  })
+  type: ItemErrorType;
+
+  @ApiProperty({
+    description: 'Human-readable error message',
+    example: 'The item name is already exist.',
+    required: false,
+    nullable: true,
+  })
+  message: string | null;
+
+  @ApiProperty({
+    description: 'Additional error payload data',
+    required: false,
+    nullable: true,
+  })
+  payload: any;
+}
+
+/**
+ * Item API Error Response Wrapper
+ */
+export class ItemApiErrorResponseDto {
+  @ApiProperty({
+    description: 'Array of error details',
+    type: [ItemErrorResponseDto],
+  })
+  errors: ItemErrorResponseDto[];
+}
diff --git a/packages/webapp/src/containers/Items/utils.tsx b/packages/webapp/src/containers/Items/utils.tsx
index 9e56d3b48..2290fc5e7 100644
--- a/packages/webapp/src/containers/Items/utils.tsx
+++ b/packages/webapp/src/containers/Items/utils.tsx
@@ -14,6 +14,18 @@ import { useSettingsSelector } from '@/hooks/state';
 import { transformItemFormData } from './ItemForm.schema';
 import { useWatch } from '@/hooks/utils';
 
+/**
+ * Error types for item operations.
+ */
+export const ItemErrorType = {
+  ItemNameExists: 'ITEM_NAME_EXISTS',
+  InventoryAccountCannotModified: 'INVENTORY_ACCOUNT_CANNOT_MODIFIED',
+  TypeCannotChangeWithItemHasTransactions: 'TYPE_CANNOT_CHANGE_WITH_ITEM_HAS_TRANSACTIONS',
+  ItemHasAssociatedTransactions: 'ITEM_HAS_ASSOCIATED_TRANSACTINS',
+  ItemHasAssociatedInventoryAdjustment: 'ITEM_HAS_ASSOCIATED_INVENTORY_ADJUSTMENT',
+  ItemHasAssociatedTransactionsPlural: 'ITEM_HAS_ASSOCIATED_TRANSACTIONS',
+} as const;
+
 const defaultInitialValues = {
   active: 1,
   name: '',
@@ -74,7 +86,7 @@ export const transitionItemTypeKeyToLabel = (itemTypeKey) => {
 // handle delete errors.
 export const handleDeleteErrors = (errors) => {
   if (
-    errors.find((error) => error.type === 'ITEM_HAS_ASSOCIATED_TRANSACTINS')
+    errors.find((error) => error.type === ItemErrorType.ItemHasAssociatedTransactions)
   ) {
     AppToaster.show({
       message: intl.get('the_item_has_associated_transactions'),
@@ -84,7 +96,7 @@ export const handleDeleteErrors = (errors) => {
 
   if (
     errors.find(
-      (error) => error.type === 'ITEM_HAS_ASSOCIATED_INVENTORY_ADJUSTMENT',
+      (error) => error.type === ItemErrorType.ItemHasAssociatedInventoryAdjustment,
     )
   ) {
     AppToaster.show({
@@ -96,7 +108,7 @@ export const handleDeleteErrors = (errors) => {
   }
   if (
     errors.find(
-      (error) => error.type === 'TYPE_CANNOT_CHANGE_WITH_ITEM_HAS_TRANSACTIONS',
+      (error) => error.type === ItemErrorType.TypeCannotChangeWithItemHasTransactions,
     )
   ) {
     AppToaster.show({
@@ -107,7 +119,7 @@ export const handleDeleteErrors = (errors) => {
     });
   }
   if (
-    errors.find((error) => error.type === 'ITEM_HAS_ASSOCIATED_TRANSACTIONS')
+    errors.find((error) => error.type === ItemErrorType.ItemHasAssociatedTransactionsPlural)
   ) {
     AppToaster.show({
       message: intl.get('item.error.you_could_not_delete_item_has_associated'),
@@ -214,10 +226,10 @@ export const transformSubmitRequestErrors = (error) => {
   } = error;
   const fields = {};
 
-  if (errors.find((e) => e.type === 'ITEM.NAME.ALREADY.EXISTS')) {
+  if (errors.find((e) => e.type === ItemErrorType.ItemNameExists)) {
     fields.name = intl.get('the_name_used_before');
   }
-  if (errors.find((e) => e.type === 'INVENTORY_ACCOUNT_CANNOT_MODIFIED')) {
+  if (errors.find((e) => e.type === ItemErrorType.InventoryAccountCannotModified)) {
     AppToaster.show({
       message: intl.get('cannot_change_item_inventory_account'),
       intent: Intent.DANGER,
@@ -225,7 +237,7 @@ export const transformSubmitRequestErrors = (error) => {
   }
   if (
     errors.find(
-      (e) => e.type === 'TYPE_CANNOT_CHANGE_WITH_ITEM_HAS_TRANSACTIONS',
+      (e) => e.type === ItemErrorType.TypeCannotChangeWithItemHasTransactions,
     )
   ) {
     AppToaster.show({