diff --git a/backend/src/chat/entities/chat.entity.ts b/backend/src/chat/entities/chat.entity.ts
index 83c1822..d6d8f22 100644
--- a/backend/src/chat/entities/chat.entity.ts
+++ b/backend/src/chat/entities/chat.entity.ts
@@ -16,22 +16,22 @@ registerEnumType(MessageType, {
 
 @ObjectType()
 export class LinkPreview {
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   url?: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   title?: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   description?: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   image?: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   siteName?: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   favicons?: string;
 }
 
@@ -67,16 +67,16 @@ export class Message {
   @Field(() => MessageType)
   type: MessageType;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   fileUrl?: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   fileName?: string;
 
   @Field(() => Int, { nullable: true })
   fileSize?: number;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   mimeType?: string;
 
   @Field(() => String, { nullable: true })
@@ -112,7 +112,7 @@ export class Conversation {
   @Field(() => Int)
   id: number;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   name?: string;
 
   @Field(() => ConversationType)
diff --git a/backend/src/dashboard/dto/dashboard-stats.type.ts b/backend/src/dashboard/dto/dashboard-stats.type.ts
index cef138b..334ebe2 100644
--- a/backend/src/dashboard/dto/dashboard-stats.type.ts
+++ b/backend/src/dashboard/dto/dashboard-stats.type.ts
@@ -71,7 +71,7 @@ export class RecentActivityItem {
   @Field()
   timestamp: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   projectName?: string;
 }
 
@@ -89,13 +89,13 @@ export class UpcomingDeadlineItem {
   @Field()
   priority: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   projectName?: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   stageName?: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   stageColor?: string;
 }
 
diff --git a/backend/src/project-stage/dto/create-project-stage.input.ts b/backend/src/project-stage/dto/create-project-stage.input.ts
index d5d1254..0389230 100644
--- a/backend/src/project-stage/dto/create-project-stage.input.ts
+++ b/backend/src/project-stage/dto/create-project-stage.input.ts
@@ -5,7 +5,7 @@ export class CreateProjectStageInput {
   @Field()
   title: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   description?: string;
 
   @Field({ defaultValue: '#808080' })
diff --git a/backend/src/project-stage/entities/project-stage.entity.ts b/backend/src/project-stage/entities/project-stage.entity.ts
index 2464925..a9e4b45 100644
--- a/backend/src/project-stage/entities/project-stage.entity.ts
+++ b/backend/src/project-stage/entities/project-stage.entity.ts
@@ -8,7 +8,7 @@ export class ProjectStage {
   @Field()
   title: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   description?: string;
 
   @Field()
diff --git a/backend/src/project/dto/create-project.input.ts b/backend/src/project/dto/create-project.input.ts
index 1a25d25..2dca669 100644
--- a/backend/src/project/dto/create-project.input.ts
+++ b/backend/src/project/dto/create-project.input.ts
@@ -12,7 +12,7 @@ export class CreateProjectInput {
   @IsSanitizedString()
   name: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   @IsSanitizedString()
   description?: string;
 
@@ -31,10 +31,10 @@ export class CreateProjectInput {
   @Field(() => Number, { nullable: true, defaultValue: 0 })
   budgetPlanned?: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   startDate?: Date;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   endDate?: Date;
 
   @Field(() => Int, { nullable: true, defaultValue: 1 })
@@ -58,7 +58,7 @@ export class CreateProjectInput {
   })
   priority?: ProjectPriority;
 
-  @Field({ nullable: true, defaultValue: 'USD' })
+  @Field(() => String, { nullable: true, defaultValue: 'USD' })
   currency?: string;
 
   @Field(() => [String], { nullable: true })
diff --git a/backend/src/project/dto/update-project.input.ts b/backend/src/project/dto/update-project.input.ts
index b6e1a43..2a67f0a 100644
--- a/backend/src/project/dto/update-project.input.ts
+++ b/backend/src/project/dto/update-project.input.ts
@@ -6,18 +6,18 @@ export class UpdateProjectInput extends PartialType(CreateProjectInput) {
   @Field(() => Int)
   id: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   actualStartDate?: Date;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   actualEndDate?: Date;
 
   @Field(() => Number, { nullable: true })
   progress?: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   archivedAt?: Date;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   key?: string;
 }
diff --git a/backend/src/project/entities/project.entity.ts b/backend/src/project/entities/project.entity.ts
index 1f547f4..fa9fca9 100644
--- a/backend/src/project/entities/project.entity.ts
+++ b/backend/src/project/entities/project.entity.ts
@@ -85,10 +85,10 @@ export class Project {
   @Field(() => Number, { defaultValue: 0 })
   budgetActual: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   startDate?: Date;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   endDate?: Date;
 
   @Field(() => Int, { defaultValue: 1 })
@@ -97,7 +97,7 @@ export class Project {
   @Field(() => ProjectMethodology, { defaultValue: ProjectMethodology.KANBAN })
   methodology: ProjectMethodology;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   key?: string;
 
   @Field(() => ProjectVisibility, { defaultValue: ProjectVisibility.TEAM })
@@ -106,10 +106,10 @@ export class Project {
   @Field(() => ProjectPriority, { defaultValue: ProjectPriority.MEDIUM })
   priority: ProjectPriority;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   actualStartDate?: Date;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   actualEndDate?: Date;
 
   @Field(() => Number, { defaultValue: 0 })
@@ -121,7 +121,7 @@ export class Project {
   @Field(() => [String], { nullable: 'items' })
   tags?: string[];
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   archivedAt?: Date;
 
   @Field(() => Number, { defaultValue: 0 })
diff --git a/backend/src/task-stage/dto/create-task-stage.input.ts b/backend/src/task-stage/dto/create-task-stage.input.ts
index 3407935..c9f1198 100644
--- a/backend/src/task-stage/dto/create-task-stage.input.ts
+++ b/backend/src/task-stage/dto/create-task-stage.input.ts
@@ -5,7 +5,7 @@ export class CreateTaskStageInput {
   @Field()
   title: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   description?: string;
 
   @Field({ defaultValue: '#808080' })
diff --git a/backend/src/task-stage/entities/task-stage.entity.ts b/backend/src/task-stage/entities/task-stage.entity.ts
index 9ca9e7f..f4755ab 100644
--- a/backend/src/task-stage/entities/task-stage.entity.ts
+++ b/backend/src/task-stage/entities/task-stage.entity.ts
@@ -8,7 +8,7 @@ export class TaskStage {
   @Field()
   title: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   description?: string;
 
   @Field()
diff --git a/backend/src/task/dto/create-task.input.ts b/backend/src/task/dto/create-task.input.ts
index 4bda3a2..7485d05 100644
--- a/backend/src/task/dto/create-task.input.ts
+++ b/backend/src/task/dto/create-task.input.ts
@@ -8,7 +8,7 @@ export class CreateTaskInput {
   @IsSanitizedString()
   title: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   @IsSanitizedString()
   description?: string;
 
@@ -27,7 +27,7 @@ export class CreateTaskInput {
   @Field(() => Number, { nullable: true, defaultValue: 0 })
   estimatedHours?: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   dueDate?: Date;
 
   @Field(() => TaskPriority, {
@@ -45,7 +45,7 @@ export class CreateTaskInput {
   @Field(() => Int, { nullable: true })
   reporterId?: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   startDate?: Date;
 
   @Field(() => [String], { nullable: true })
diff --git a/backend/src/task/dto/update-task.input.ts b/backend/src/task/dto/update-task.input.ts
index 3552013..fe66c62 100644
--- a/backend/src/task/dto/update-task.input.ts
+++ b/backend/src/task/dto/update-task.input.ts
@@ -6,7 +6,7 @@ export class UpdateTaskInput extends PartialType(CreateTaskInput) {
   @Field(() => Int)
   id: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   completedAt?: Date;
 
   @Field(() => Number, { nullable: true })
@@ -15,6 +15,6 @@ export class UpdateTaskInput extends PartialType(CreateTaskInput) {
   @Field(() => Number, { nullable: true })
   progress?: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   deletedAt?: Date;
 }
diff --git a/backend/src/task/entities/task.entity.ts b/backend/src/task/entities/task.entity.ts
index a548012..ce4badd 100644
--- a/backend/src/task/entities/task.entity.ts
+++ b/backend/src/task/entities/task.entity.ts
@@ -21,7 +21,7 @@ export class Task extends Base {
   @Field()
   title: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   description?: string;
 
   @Field(() => Int)
@@ -54,7 +54,7 @@ export class Task extends Base {
   @Field(() => Number, { defaultValue: 0 })
   estimatedHours: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   dueDate?: Date;
 
   @Field(() => TaskPriority, { defaultValue: TaskPriority.MEDIUM })
@@ -81,10 +81,10 @@ export class Task extends Base {
   @Field(() => User, { nullable: true })
   reporter?: User;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   startDate?: Date;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   completedAt?: Date;
 
   @Field(() => Number, { defaultValue: 0 })
@@ -96,6 +96,6 @@ export class Task extends Base {
   @Field(() => [String], { nullable: 'items' })
   tags?: string[];
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   deletedAt?: Date;
 }
diff --git a/backend/src/timesheet/dto/create-timesheet.input.ts b/backend/src/timesheet/dto/create-timesheet.input.ts
index 93897ac..8887767 100644
--- a/backend/src/timesheet/dto/create-timesheet.input.ts
+++ b/backend/src/timesheet/dto/create-timesheet.input.ts
@@ -21,13 +21,13 @@ export class CreateTimesheetInput {
   @Field(() => Int)
   taskId: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   startTime?: Date;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   endTime?: Date;
 
-  @Field({ nullable: true, defaultValue: true })
+  @Field(() => Boolean, { nullable: true, defaultValue: true })
   billable?: boolean;
 
   @Field(() => Number, { nullable: true })
diff --git a/backend/src/timesheet/dto/update-timesheet.input.ts b/backend/src/timesheet/dto/update-timesheet.input.ts
index 3f5a30e..720b785 100644
--- a/backend/src/timesheet/dto/update-timesheet.input.ts
+++ b/backend/src/timesheet/dto/update-timesheet.input.ts
@@ -13,7 +13,7 @@ export class UpdateTimesheetInput extends PartialType(CreateTimesheetInput) {
   @Field(() => Int, { nullable: true })
   approvedById?: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   approvedAt?: Date;
 
   @Field(() => Number, { nullable: true })
diff --git a/backend/src/timesheet/entities/timesheet.entity.ts b/backend/src/timesheet/entities/timesheet.entity.ts
index 07f84ea..3fa3cac 100644
--- a/backend/src/timesheet/entities/timesheet.entity.ts
+++ b/backend/src/timesheet/entities/timesheet.entity.ts
@@ -46,10 +46,10 @@ export class Timesheet extends Base {
   @Field(() => Int)
   taskId: number;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   startTime?: Date;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   endTime?: Date;
 
   @Field({ defaultValue: true })
@@ -73,7 +73,7 @@ export class Timesheet extends Base {
   @Field(() => User, { nullable: true })
   approvedBy?: User;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   approvedAt?: Date;
 
   @Field(() => [String], { nullable: 'items' })
diff --git a/backend/src/user/dto/create-user.input.ts b/backend/src/user/dto/create-user.input.ts
index b30119b..c071534 100644
--- a/backend/src/user/dto/create-user.input.ts
+++ b/backend/src/user/dto/create-user.input.ts
@@ -19,32 +19,32 @@ export class CreateUserInput {
   @Field()
   password: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   phone: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   mobile: string;
 
   @Field()
   @IsSanitizedString()
   firstName: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   @IsSanitizedString()
   lastName: string;
 
   @Field({ defaultValue: true })
   status: boolean;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   @IsSanitizedString()
   address: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   @IsSanitizedString()
   bio: string;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   birthDate: Date;
 
   @Field(() => UserRole, { defaultValue: UserRole.USER })
diff --git a/backend/src/user/entities/user.entity.ts b/backend/src/user/entities/user.entity.ts
index eb0ec36..f5373ad 100644
--- a/backend/src/user/entities/user.entity.ts
+++ b/backend/src/user/entities/user.entity.ts
@@ -14,28 +14,28 @@ export class User extends Base {
   @Field()
   password: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   phone?: string | null;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   mobile?: string | null;
 
   @Field()
   firstName: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   lastName?: string | null;
 
   @Field({ defaultValue: true })
   status: boolean;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   address?: string | null;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   bio?: string | null;
 
-  @Field({ nullable: true })
+  @Field(() => Date, { nullable: true })
   birthDate?: Date | null;
 
   @Field()
diff --git a/backend/src/workspace/dto/create-workspace.input.ts b/backend/src/workspace/dto/create-workspace.input.ts
index f43bee6..5ea42ed 100644
--- a/backend/src/workspace/dto/create-workspace.input.ts
+++ b/backend/src/workspace/dto/create-workspace.input.ts
@@ -7,7 +7,7 @@ export class CreateWorkspaceInput {
   @IsSanitizedString()
   name: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   @IsSanitizedString()
   description?: string;
 }
diff --git a/backend/src/workspace/entities/workspace.entity.ts b/backend/src/workspace/entities/workspace.entity.ts
index 82a159e..e0d5eb7 100644
--- a/backend/src/workspace/entities/workspace.entity.ts
+++ b/backend/src/workspace/entities/workspace.entity.ts
@@ -10,7 +10,7 @@ export class Workspace {
   @Field()
   name: string;
 
-  @Field({ nullable: true })
+  @Field(() => String, { nullable: true })
   description?: string | null;
 
   @Field(() => [WorkspaceMember], { nullable: 'items' })