diff --git a/backend/services/notification-service/src/interface/http/dto/notification-query.dto.ts b/backend/services/notification-service/src/interface/http/dto/notification-query.dto.ts
index 8fa79a1..99443a1 100644
--- a/backend/services/notification-service/src/interface/http/dto/notification-query.dto.ts
+++ b/backend/services/notification-service/src/interface/http/dto/notification-query.dto.ts
@@ -1,4 +1,4 @@
-import { IsOptional, IsInt, Min, Max } from 'class-validator';
+import { IsOptional, IsInt, IsString, Min, Max } from 'class-validator';
 import { Type } from 'class-transformer';
 import { ApiPropertyOptional } from '@nestjs/swagger';
 
@@ -17,4 +17,9 @@ export class NotificationQueryDto {
   @Min(1)
   @Max(100)
   limit?: number = 20;
+
+  @ApiPropertyOptional({ description: 'Filter by notification type (e.g. SYSTEM, ACTIVITY)' })
+  @IsOptional()
+  @IsString()
+  type?: string;
 }