diff --git a/src/Squidex/app/features/administration/pages/event-consumers/event-consumers-page.component.ts b/src/Squidex/app/features/administration/pages/event-consumers/event-consumers-page.component.ts
index ce123c686..a87cd7bc3 100644
--- a/src/Squidex/app/features/administration/pages/event-consumers/event-consumers-page.component.ts
+++ b/src/Squidex/app/features/administration/pages/event-consumers/event-consumers-page.component.ts
@@ -9,8 +9,8 @@ import { Component, OnDestroy, OnInit } from '@angular/core';
 import { Observable, Subscription } from 'rxjs';
 
 import {
-    AppContext,
     fadeAnimation,
+    DialogService,
     ImmutableArray,
     ModalView
 } from 'shared';
@@ -21,9 +21,6 @@ import { EventConsumerDto, EventConsumersService } from './../../services/event-
     selector: 'sqx-event-consumers-page',
     styleUrls: ['./event-consumers-page.component.scss'],
     templateUrl: './event-consumers-page.component.html',
-    providers: [
-        AppContext
-    ],
     animations: [
         fadeAnimation
     ]
@@ -35,7 +32,8 @@ export class EventConsumersPageComponent implements OnDestroy, OnInit {
     public eventConsumerError = '';
     public eventConsumers = ImmutableArray.empty<EventConsumerDto>();
 
-    constructor(public readonly ctx: AppContext,
+    constructor(
+        private readonly dialogs: DialogService,
         private readonly eventConsumersService: EventConsumersService
     ) {
     }
@@ -59,11 +57,11 @@ export class EventConsumersPageComponent implements OnDestroy, OnInit {
                 this.eventConsumers = ImmutableArray.of(dtos);
 
                 if (showInfo) {
-                    this.ctx.notifyInfo('Event Consumers reloaded.');
+                    this.dialogs.notifyInfo('Event Consumers reloaded.');
                 }
             }, error => {
                 if (showError) {
-                    this.ctx.notifyError(error);
+                    this.dialogs.notifyError(error);
                 }
             });
     }
@@ -73,7 +71,7 @@ export class EventConsumersPageComponent implements OnDestroy, OnInit {
             .subscribe(() => {
                 this.eventConsumers = this.eventConsumers.replaceBy('name', consumer.start());
             }, error => {
-                this.ctx.notifyError(error);
+                this.dialogs.notifyError(error);
             });
     }
 
@@ -82,7 +80,7 @@ export class EventConsumersPageComponent implements OnDestroy, OnInit {
             .subscribe(() => {
                 this.eventConsumers = this.eventConsumers.replaceBy('name', consumer.stop());
             }, error => {
-                this.ctx.notifyError(error);
+                this.dialogs.notifyError(error);
             });
     }
 
@@ -91,7 +89,7 @@ export class EventConsumersPageComponent implements OnDestroy, OnInit {
             .subscribe(() => {
                 this.eventConsumers = this.eventConsumers.replaceBy('name', consumer.reset());
             }, error => {
-                this.ctx.notifyError(error);
+                this.dialogs.notifyError(error);
             });
     }
 
diff --git a/src/Squidex/app/features/administration/pages/users/user-page.component.ts b/src/Squidex/app/features/administration/pages/users/user-page.component.ts
index d53e135e1..eabe23c0f 100644
--- a/src/Squidex/app/features/administration/pages/users/user-page.component.ts
+++ b/src/Squidex/app/features/administration/pages/users/user-page.component.ts
@@ -7,10 +7,10 @@
 
 import { Component, OnDestroy, OnInit } from '@angular/core';
 import { FormBuilder, Validators } from '@angular/forms';
-import { Router } from '@angular/router';
+import { ActivatedRoute, Router } from '@angular/router';
 import { Subscription } from 'rxjs';
 
-import { AppContext, ValidatorsEx } from 'shared';
+import { AuthService, ValidatorsEx } from 'shared';
 
 import { UserDto } from './../../services/users.service';
 import { UsersState } from './../../state/users.state';
@@ -18,10 +18,7 @@ import { UsersState } from './../../state/users.state';
 @Component({
     selector: 'sqx-user-page',
     styleUrls: ['./user-page.component.scss'],
-    templateUrl: './user-page.component.html',
-    providers: [
-        AppContext
-    ]
+    templateUrl: './user-page.component.html'
 })
 export class UserPageComponent implements OnDestroy, OnInit {
     private selectedUserSubscription: Subscription;
@@ -55,10 +52,12 @@ export class UserPageComponent implements OnDestroy, OnInit {
 
     public isCurrentUser = false;
 
-    constructor(public readonly ctx: AppContext,
+    constructor(
+        private readonly authService: AuthService,
         private readonly formBuilder: FormBuilder,
+        private readonly route: ActivatedRoute,
         private readonly router: Router,
-        private readonly state: UsersState
+        private readonly usersState: UsersState
     ) {
     }
 
@@ -68,7 +67,7 @@ export class UserPageComponent implements OnDestroy, OnInit {
 
     public ngOnInit() {
         this.selectedUserSubscription =
-            this.state.selectedUser.subscribe(user => this.setupAndPopulateForm(user!));
+            this.usersState.selectedUser.subscribe(user => this.setupAndPopulateForm(user!));
     }
 
     public save() {
@@ -80,14 +79,14 @@ export class UserPageComponent implements OnDestroy, OnInit {
             const requestDto = this.userForm.value;
 
             if (!this.user) {
-                this.state.createUser(requestDto)
+                this.usersState.createUser(requestDto)
                     .subscribe(user => {
                         this.back();
                     }, error => {
                         this.resetFormState(error.displayMessage);
                     });
             } else {
-                this.state.updateUser(this.user!, requestDto)
+                this.usersState.updateUser(this.user!, requestDto)
                     .subscribe(() => {
                         this.resetFormState();
                     }, error => {
@@ -98,13 +97,13 @@ export class UserPageComponent implements OnDestroy, OnInit {
     }
 
     private back() {
-        this.router.navigate(['../'], { relativeTo: this.ctx.route, replaceUrl: true });
+        this.router.navigate(['../'], { relativeTo: this.route, replaceUrl: true });
     }
 
     private setupAndPopulateForm(user: UserDto | null) {
         this.user = user;
 
-        this.isCurrentUser = user !== null && user.id === this.ctx.userId;
+        this.isCurrentUser = user !== null && user.id === this.authService.user!.id;
 
         this.userForm.controls['password'].setValidators(
             user ?
diff --git a/src/Squidex/app/features/administration/pages/users/users-page.component.html b/src/Squidex/app/features/administration/pages/users/users-page.component.html
index d23dbcc26..325fe8cfd 100644
--- a/src/Squidex/app/features/administration/pages/users/users-page.component.html
+++ b/src/Squidex/app/features/administration/pages/users/users-page.component.html
@@ -56,7 +56,7 @@
                 <div sqxIgnoreScrollbar>
                     <table class="table table-items table-fixed">
                         <tbody>
-                            <ng-template ngFor let-user [ngForOf]="state.usersItems | async" [ngForTrackBy]="state.trackBy">
+                            <ng-template ngFor let-user [ngForOf]="state.usersItems | async" [ngForTrackBy]="state.trackByUser">
                                 <tr [routerLink]="user.id" routerLinkActive="active">
                                     <td class="cell-user">
                                         <img class="user-picture" [attr.title]="user.name" [attr.src]="user | sqxUserDtoPicture" />
@@ -88,7 +88,7 @@
                 </div>
             </div>
 
-            <ng-container *ngIf="state.usersPager | async as pager">
+            <ng-container *ngIf="usersState.usersPager | async as pager">
                 <div class="grid-footer clearfix" *ngIf="pager.numberOfItems > 0">
                     <div class="float-right pagination">
                         <span class="pagination-text">{{pager.itemFirst}}-{{pager.itemLast}} of {{pager.numberOfItems}}</span>
diff --git a/src/Squidex/app/features/administration/pages/users/users-page.component.ts b/src/Squidex/app/features/administration/pages/users/users-page.component.ts
index cbd38614b..f1c6c79cc 100644
--- a/src/Squidex/app/features/administration/pages/users/users-page.component.ts
+++ b/src/Squidex/app/features/administration/pages/users/users-page.component.ts
@@ -8,7 +8,7 @@
 import { Component, OnInit } from '@angular/core';
 import { FormControl } from '@angular/forms';
 
-import { AppContext } from 'shared';
+import { DialogService } from 'shared';
 
 import { UserDto } from './../../services/users.service';
 import { UsersState } from './../../state/users.state';
@@ -16,16 +16,13 @@ import { UsersState } from './../../state/users.state';
 @Component({
     selector: 'sqx-users-page',
     styleUrls: ['./users-page.component.scss'],
-    templateUrl: './users-page.component.html',
-    providers: [
-        AppContext
-    ]
+    templateUrl: './users-page.component.html'
 })
 export class UsersPageComponent implements OnInit {
     public usersFilter = new FormControl();
 
-    constructor(public readonly ctx: AppContext,
-        public readonly state: UsersState
+    constructor(public readonly usersState: UsersState,
+        private readonly dialogs: DialogService
     ) {
     }
 
@@ -34,32 +31,32 @@ export class UsersPageComponent implements OnInit {
     }
 
     public search() {
-        this.state.search(this.usersFilter.value).subscribe();
+        this.usersState.search(this.usersFilter.value).subscribe();
     }
 
     public load(showInfo = false) {
-        this.state.loadUsers()
+        this.usersState.loadUsers()
             .subscribe(() => {
                 if (showInfo) {
-                    this.ctx.notifyInfo('Users reloaded.');
+                    this.dialogs.notifyInfo('Users reloaded.');
                 }
             });
     }
 
     public lock(user: UserDto) {
-        this.state.lockUser(user).subscribe();
+        this.usersState.lockUser(user).subscribe();
     }
 
     public unlock(user: UserDto) {
-        this.state.unlockUser(user).subscribe();
+        this.usersState.unlockUser(user).subscribe();
     }
 
     public goPrev() {
-        this.state.goPrev().subscribe();
+        this.usersState.goPrev().subscribe();
     }
 
     public goNext() {
-        this.state.goNext().subscribe();
+        this.usersState.goNext().subscribe();
     }
 }
 
diff --git a/src/Squidex/app/features/administration/state/users.state.ts b/src/Squidex/app/features/administration/state/users.state.ts
index e7e4dc66d..86e7b19a0 100644
--- a/src/Squidex/app/features/administration/state/users.state.ts
+++ b/src/Squidex/app/features/administration/state/users.state.ts
@@ -12,9 +12,7 @@ import 'framework/utils/rxjs-extensions';
 
 import {
     DialogService,
-    ErrorDto,
     ImmutableArray,
-    Notification,
     Pager
 } from 'shared';
 
@@ -59,7 +57,7 @@ export class UsersState {
 
     public loadUsers(): Observable<any> {
         return this.usersService.getUsers(this.usersPager.value.pageSize, this.usersPager.value.skip, this.usersQuery.value)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dtos => {
                 this.users.nextBy(v => ImmutableArray.of(dtos.items));
                 this.usersPager.nextBy(v => v.setCount(dtos.total));
@@ -77,7 +75,7 @@ export class UsersState {
     public updateUser(user: UserDto, request: CreateUserDto): Observable<any> {
         return this.usersService.putUser(user.id, request)
             .do(() => {
-                this.dialogs.notify(Notification.info('User saved successsfull'));
+                this.dialogs.notifyInfo('User saved successsfull');
 
                 this.replaceUser(user.update(request.email, request.displayName));
             });
@@ -85,7 +83,7 @@ export class UsersState {
 
     public lockUser(user: UserDto): Observable<any> {
         return this.usersService.lockUser(user.id)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(() => {
                 this.replaceUser(user.lock());
             });
@@ -93,7 +91,7 @@ export class UsersState {
 
     public unlockUser(user: UserDto): Observable<any> {
         return this.usersService.unlockUser(user.id)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(() => {
                 this.replaceUser(user.unlock());
             });
@@ -118,7 +116,7 @@ export class UsersState {
         return this.loadUsers();
     }
 
-    public trackBy(index: number, user: UserDto): any {
+    public trackByUser(index: number, user: UserDto): any {
         return user.id;
     }
 
@@ -127,14 +125,4 @@ export class UsersState {
 
         this.selectedUser.nextBy(v => v !== null && v.id === user.id ? user : v);
     }
-
-    private notifyError(error: string | ErrorDto) {
-        if (error instanceof ErrorDto) {
-            this.dialogs.notify(Notification.error(error.displayMessage));
-        } else {
-            this.dialogs.notify(Notification.error(error));
-        }
-
-        return Observable.throw(error);
-    }
 }
\ No newline at end of file
diff --git a/src/Squidex/app/features/schemas/state/schemas.state.ts b/src/Squidex/app/features/schemas/state/schemas.state.ts
index 81b083e67..e7d044ff9 100644
--- a/src/Squidex/app/features/schemas/state/schemas.state.ts
+++ b/src/Squidex/app/features/schemas/state/schemas.state.ts
@@ -17,10 +17,8 @@ import {
     CreateSchemaDto,
     DateTime,
     DialogService,
-    ErrorDto,
     FieldDto,
     ImmutableArray,
-    Notification,
     SchemaDto,
     SchemaDetailsDto,
     SchemasService,
@@ -73,7 +71,7 @@ export class SchemasState {
 
     public load(): Observable<any> {
         return this.schemasService.getSchemas(this.app)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dtos => {
                 this.schemasItems.nextBy(v => ImmutableArray.of(dtos));
             });
@@ -95,7 +93,7 @@ export class SchemasState {
 
     public publish(schema: SchemaDto): Observable<any> {
         return this.schemasService.publishSchema(this.app, schema.name, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.publish(this.user, dto.version));
             });
@@ -103,7 +101,7 @@ export class SchemasState {
 
     public unpublish(schema: SchemaDto): Observable<any> {
         return this.schemasService.unpublishSchema(this.app, schema.name, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.unpublish(this.user, dto.version));
             });
@@ -111,7 +109,7 @@ export class SchemasState {
 
     public enableField(schema: SchemaDetailsDto, field: FieldDto): Observable<any> {
         return this.schemasService.enableField(this.app, schema.name, field.fieldId, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.updateField(field.enable(), this.user, dto.version));
             });
@@ -119,7 +117,7 @@ export class SchemasState {
 
     public disableField(schema: SchemaDetailsDto, field: FieldDto): Observable<any> {
         return this.schemasService.disableField(this.app, schema.name, field.fieldId, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.updateField(field.disable(), this.user, dto.version));
             });
@@ -127,7 +125,7 @@ export class SchemasState {
 
     public lockField(schema: SchemaDetailsDto, field: FieldDto): Observable<any> {
         return this.schemasService.lockField(this.app, schema.name, field.fieldId, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.updateField(field.lock(), this.user, dto.version));
             });
@@ -135,7 +133,7 @@ export class SchemasState {
 
     public showField(schema: SchemaDetailsDto, field: FieldDto): Observable<any> {
         return this.schemasService.showField(this.app, schema.name, field.fieldId, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.updateField(field.show(), this.user, dto.version));
             });
@@ -143,7 +141,7 @@ export class SchemasState {
 
     public hideField(schema: SchemaDetailsDto, field: FieldDto): Observable<any> {
         return this.schemasService.hideField(this.app, schema.name, field.fieldId, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.updateField(field.hide(), this.user, dto.version));
             });
@@ -151,7 +149,7 @@ export class SchemasState {
 
     public deleteField(schema: SchemaDetailsDto, field: FieldDto): Observable<any> {
         return this.schemasService.deleteField(this.app, schema.name, field.fieldId, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.removeField(field, this.user, dto.version));
             });
@@ -159,7 +157,7 @@ export class SchemasState {
 
     public sortFields(schema: SchemaDetailsDto, fields: FieldDto[]): Observable<any> {
         return this.schemasService.putFieldOrdering(this.app, schema.name, fields.map(t => t.fieldId), schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.replaceFields(fields, this.user, dto.version));
             });
@@ -167,7 +165,7 @@ export class SchemasState {
 
     public updateField(schema: SchemaDetailsDto, field: FieldDto, request: UpdateFieldDto): Observable<any> {
         return this.schemasService.putField(this.app, schema.name, field.fieldId, request, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.updateField(field.update(request.properties), this.user, dto.version));
             });
@@ -175,7 +173,7 @@ export class SchemasState {
 
     public configureScripts(schema: SchemaDetailsDto, request: UpdateSchemaScriptsDto): Observable<any> {
         return this.schemasService.putSchemaScripts(this.app, schema.name, request, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.configureScripts(request, this.user, dto.version));
             });
@@ -183,7 +181,7 @@ export class SchemasState {
 
     public update(schema: SchemaDetailsDto, request: UpdateSchemaDto): Observable<any> {
         return this.schemasService.putSchema(this.app, schema.name, request, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.replaceSchema(schema.update(request, this.user, dto.version));
             });
@@ -191,7 +189,7 @@ export class SchemasState {
 
     public delete(schema: SchemaDto): Observable<any> {
         return this.schemasService.deleteSchema(this.app, schema.name, schema.version)
-            .catch(error => this.notifyError(error))
+            .catch(error => this.dialogs.notifyError(error))
             .do(dto => {
                 this.schemasItems.nextBy(v => v.filter(s => s.id !== schema.id));
             });
@@ -210,14 +208,4 @@ export class SchemasState {
     public trackByField(index: number, field: FieldDto): any {
         return field.fieldId;
     }
-
-    private notifyError(error: string | ErrorDto) {
-        if (error instanceof ErrorDto) {
-            this.dialogs.notify(Notification.error(error.displayMessage));
-        } else {
-            this.dialogs.notify(Notification.error(error));
-        }
-
-        return Observable.throw(error);
-    }
 }
\ No newline at end of file
diff --git a/src/Squidex/app/framework/angular/http-extensions-impl.ts b/src/Squidex/app/framework/angular/http-extensions-impl.ts
index f99f383b7..3786707c3 100644
--- a/src/Squidex/app/framework/angular/http-extensions-impl.ts
+++ b/src/Squidex/app/framework/angular/http-extensions-impl.ts
@@ -8,65 +8,9 @@
 import { HttpClient, HttpErrorResponse, HttpHeaders, HttpResponse } from '@angular/common/http';
 import { Observable } from 'rxjs';
 
-import { Version } from './../utils/version';
+import { ErrorDto } from './../utils/error';
 
-export class Versioned<T> {
-    constructor(
-        public readonly version: Version,
-        public readonly payload: T
-    ) {
-    }
-}
-
-function formatMessage(message: string, details?: string[]) {
-    const appendLast = (row: string, char: string) => {
-        const last = row[row.length - 1];
-
-        if (last !== char) {
-            return row + char;
-        } else {
-            return row;
-        }
-    };
-
-    const removeLast = (row: string, char: string) => {
-        const last = row[row.length - 1];
-
-        if (last === char) {
-            return row.substr(0, row.length - 1);
-        } else {
-            return row;
-        }
-    };
-
-    if (details && details.length > 1) {
-        let result = appendLast(message, '.') + '<ul>';
-
-        for (let detail of details) {
-            result += `<li>${appendLast(detail, '.')}</li>`;
-        }
-
-        result = result + '</ul>';
-
-        return result;
-    } else if (details && details.length === 1) {
-        return `${appendLast(removeLast(message, '.'), ':')} ${appendLast(details[0], '.')}`;
-    } else {
-        return appendLast(message, '.');
-    }
-}
-
-export class ErrorDto {
-    public readonly displayMessage: string;
-
-    constructor(
-        public readonly statusCode: number,
-        public readonly message: string,
-        public readonly details: string[] = []
-    ) {
-        this.displayMessage = formatMessage(message, details);
-    }
-}
+import { Version, Versioned } from './../utils/version';
 
 export module HTTP {
     export function getVersioned<T>(http: HttpClient, url: string, version?: Version): Observable<Versioned<HttpResponse<T>>> {
diff --git a/src/Squidex/app/framework/declarations.ts b/src/Squidex/app/framework/declarations.ts
index e0b8c3aea..0e36f1409 100644
--- a/src/Squidex/app/framework/declarations.ts
+++ b/src/Squidex/app/framework/declarations.ts
@@ -67,6 +67,7 @@ export * from './services/title.service';
 export * from './utils/date-helper';
 export * from './utils/date-time';
 export * from './utils/duration';
+export * from './utils/error';
 export * from './utils/immutable-array';
 export * from './utils/math-helper';
 export * from './utils/modal-view';
diff --git a/src/Squidex/app/framework/services/dialog.service.ts b/src/Squidex/app/framework/services/dialog.service.ts
index 44a0b98b4..72b9a0e00 100644
--- a/src/Squidex/app/framework/services/dialog.service.ts
+++ b/src/Squidex/app/framework/services/dialog.service.ts
@@ -8,6 +8,8 @@
 import { Injectable } from '@angular/core';
 import { Observable, Subject } from 'rxjs';
 
+import { ErrorDto } from './../utils/error';
+
 export const DialogServiceFactory = () => {
     return new DialogService();
 };
@@ -61,6 +63,20 @@ export class DialogService {
         return this.notificationsStream$;
     }
 
+    public notifyError(error: string | ErrorDto) {
+        if (error instanceof ErrorDto) {
+            this.notify(Notification.error(error.displayMessage));
+        } else {
+            this.notify(Notification.error(error));
+        }
+
+        return Observable.throw(error);
+    }
+
+    public notifyInfo(text: string) {
+        this.notificationsStream$.next(Notification.info(text));
+    }
+
     public notify(notification: Notification) {
         this.notificationsStream$.next(notification);
     }
diff --git a/src/Squidex/app/framework/utils/error.spec.ts b/src/Squidex/app/framework/utils/error.spec.ts
new file mode 100644
index 000000000..163b71075
--- /dev/null
+++ b/src/Squidex/app/framework/utils/error.spec.ts
@@ -0,0 +1,40 @@
+/*
+ * Squidex Headless CMS
+ *
+ * @license
+ * Copyright (c) Squidex UG (haftungsbeschränkt). All rights reserved.
+ */
+
+import { ErrorDto } from './../';
+
+describe('ErrorDto', () => {
+    it('Should create simple message when no details are specified.', () => {
+        const error = new ErrorDto(500, 'Error Message.');
+
+        expect(error.displayMessage).toBe('Error Message.');
+    });
+
+    it('Should append dot to message', () => {
+        const error = new ErrorDto(500, 'Error Message');
+
+        expect(error.displayMessage).toBe('Error Message.');
+    });
+
+    it('Should create simple message when detail has one item', () => {
+        const error = new ErrorDto(500, 'Error Message.', ['Detail Message.']);
+
+        expect(error.displayMessage).toBe('Error Message: Detail Message.');
+    });
+
+    it('Should create append do to simple message when detail has one item', () => {
+        const error = new ErrorDto(500, 'Error Message', ['Detail Message']);
+
+        expect(error.displayMessage).toBe('Error Message: Detail Message.');
+    });
+
+    it('Should create html list when error has more items.', () => {
+        const error = new ErrorDto(500, 'Error Message', ['Detail1.', 'Detail2.']);
+
+        expect(error.displayMessage).toBe('Error Message.<ul><li>Detail1.</li><li>Detail2.</li></ul>');
+    });
+});
\ No newline at end of file
diff --git a/src/Squidex/app/framework/utils/error.ts b/src/Squidex/app/framework/utils/error.ts
new file mode 100644
index 000000000..72bac2567
--- /dev/null
+++ b/src/Squidex/app/framework/utils/error.ts
@@ -0,0 +1,57 @@
+/*
+ * Squidex Headless CMS
+ *
+ * @license
+ * Copyright (c) Squidex UG (haftungsbeschränkt). All rights reserved.
+ */
+
+export class ErrorDto {
+    public readonly displayMessage: string;
+
+    constructor(
+        public readonly statusCode: number,
+        public readonly message: string,
+        public readonly details: string[] = []
+    ) {
+        this.displayMessage = formatMessage(message, details);
+    }
+}
+
+
+function formatMessage(message: string, details?: string[]) {
+    const appendLast = (row: string, char: string) => {
+        const last = row[row.length - 1];
+
+        if (last !== char) {
+            return row + char;
+        } else {
+            return row;
+        }
+    };
+
+    const removeLast = (row: string, char: string) => {
+        const last = row[row.length - 1];
+
+        if (last === char) {
+            return row.substr(0, row.length - 1);
+        } else {
+            return row;
+        }
+    };
+
+    if (details && details.length > 1) {
+        let result = appendLast(message, '.') + '<ul>';
+
+        for (let detail of details) {
+            result += `<li>${appendLast(detail, '.')}</li>`;
+        }
+
+        result = result + '</ul>';
+
+        return result;
+    } else if (details && details.length === 1) {
+        return `${appendLast(removeLast(message, '.'), ':')} ${appendLast(details[0], '.')}`;
+    } else {
+        return appendLast(message, '.');
+    }
+}
\ No newline at end of file
diff --git a/src/Squidex/app/framework/utils/version.spec.ts b/src/Squidex/app/framework/utils/version.spec.ts
index ce2d7637d..5ecf6160d 100644
--- a/src/Squidex/app/framework/utils/version.spec.ts
+++ b/src/Squidex/app/framework/utils/version.spec.ts
@@ -5,7 +5,7 @@
  * Copyright (c) Squidex UG (haftungsbeschränkt). All rights reserved.
  */
 
-import { Version } from './../';
+import { Version, Versioned } from './../';
 
 describe('Version', () => {
     it('should initialize with init value', () => {
@@ -13,4 +13,13 @@ describe('Version', () => {
 
         expect(version.value).toBe('1.0');
     });
+});
+
+describe('Versioned', () => {
+    it('should initialize with version and payload', () => {
+        const versioned = new Versioned<number>(new Version('1.0'), 123);
+
+        expect(versioned.version.value).toBe('1.0');
+        expect(versioned.payload).toBe(123);
+    });
 });
\ No newline at end of file
diff --git a/src/Squidex/app/framework/utils/version.ts b/src/Squidex/app/framework/utils/version.ts
index 045ea8639..92016cd90 100644
--- a/src/Squidex/app/framework/utils/version.ts
+++ b/src/Squidex/app/framework/utils/version.ts
@@ -10,4 +10,12 @@ export class Version {
         public readonly value: string
     ) {
     }
+}
+
+export class Versioned<T> {
+    constructor(
+        public readonly version: Version,
+        public readonly payload: T
+    ) {
+    }
 }
\ No newline at end of file