diff --git a/backend/docker.sh b/backend/docker.sh
index cade815..8ccc494 100644
--- a/backend/docker.sh
+++ b/backend/docker.sh
@@ -18,6 +18,6 @@ fi
 echo "Installing packages"
 npm install
 echo "Running application"
-npm run rebuild
+npm run clean
 wait-for-it database:3306 -t 0
 npm run start:watch
diff --git a/backend/src/graphql-resolvers/user.resolver.ts b/backend/src/graphql-resolvers/user.resolver.ts
index aaf231c..7275fb8 100644
--- a/backend/src/graphql-resolvers/user.resolver.ts
+++ b/backend/src/graphql-resolvers/user.resolver.ts
@@ -1,4 +1,4 @@
-import { arg, authorized, GraphQLBindings, ID, mutation, query, resolver, ResolverData } from '@loopback/graphql';
+import { arg, authorized, GraphQLBindings, ID, Int, mutation, query, resolver, ResolverData } from '@loopback/graphql';
 import { User } from '../models';
 import { repository } from '@loopback/repository';
 import { RevTokenRepository, UserRepository } from '../repositories';
@@ -10,9 +10,10 @@ import { SecurityBindings, UserProfile } from '@loopback/security';
 import { genSalt, hash } from 'bcryptjs';
 import { UserRegisterInput } from '../graphql-types/input/user-register.input';
 import { validated } from '../helpers';
-import { LoginResult } from '../graphql-types/user';
+import { LoginResult, UserList } from '../graphql-types/user';
 import { UserUpdateInput } from '../graphql-types/input/user-update.input';
 import { SzakdolgozatBindings } from '../bindings';
+import { listResponse } from '../graphql-types/list';
 
 @resolver(of => User)
 export class UserResolver {
@@ -69,20 +70,26 @@ export class UserResolver {
 
     @authorized()
     @query(returns => User, {name: 'user'})
-    async findById(@arg('id') id: number): Promise<User> {
+    async findById(@arg('id', returns => ID) id: number): Promise<User> {
         return this.userRepository.findById(id);
     }
 
+    @authorized()
+    @query(returns => [User])
+    async users(@arg('limit', returns => Int) limit: number, @arg('offset', returns => Int) offset: number) {
+        return await listResponse(this.userRepository, offset, limit, UserList);
+    }
+
     @authorized()
     @mutation(returns => Boolean)
-    async userUpdate(@arg('id', returns => ID) id: number, @arg('user') user: UserUpdateInput): Promise<boolean> {
-        if (id === +this.user?.id) { //TODO: this.user
+    async userUpdate(@arg('user') user: UserUpdateInput): Promise<boolean> {
+        if (user.id === +this.user?.id) { //TODO: this.user
             const loggedInUser = await this.userService.findUserById(this.user.id);
             if (user.isAdmin !== undefined && loggedInUser.isAdmin !== user.isAdmin) {
                 throw new Error('Cannot change admin status of self');
             }
         }
-        await this.userRepository.updateById(id, user);
+        await this.userRepository.updateById(user.id, user);
         return true;
     }
 
diff --git a/backend/src/graphql-types/input/user-update.input.ts b/backend/src/graphql-types/input/user-update.input.ts
index ae2386d..bcd246c 100644
--- a/backend/src/graphql-types/input/user-update.input.ts
+++ b/backend/src/graphql-types/input/user-update.input.ts
@@ -1,10 +1,12 @@
 import { User } from '../../models';
-import { field, inputType } from '@loopback/graphql';
+import { field, ID, inputType } from '@loopback/graphql';
 import { UserProperties } from '../user';
 import { property } from '@loopback/repository';
 
 @inputType()
-export class UserUpdateInput implements Partial<Pick<User, 'name' | 'email' | 'password' | 'isAdmin'>> {
+export class UserUpdateInput implements Partial<Pick<User, 'id' | 'name' | 'email' | 'password' | 'isAdmin'>> {
+    @field(returns => ID)
+    id: number;
     @field({nullable: true})
     @property(UserProperties.email)
     email?: string;
diff --git a/backend/src/graphql-types/list.ts b/backend/src/graphql-types/list.ts
index ba22e1e..a0ffa8c 100644
--- a/backend/src/graphql-types/list.ts
+++ b/backend/src/graphql-types/list.ts
@@ -14,7 +14,7 @@ export interface ListResponse<T> {
     list: T[];
 }
 
-export async function listResponse<T extends Entity, U extends ListResponse<T>>(repo: DefaultCrudRepository<T, number>, offset: number, limit: number, listType: ClassType<U>) {
+export async function listResponse<T extends Entity, U extends ListResponse<Partial<T>>>(repo: DefaultCrudRepository<T, number>, offset: number, limit: number, listType: ClassType<U>) {
     const list = new listType();
     list.list = await repo.find({offset, limit});
     list.count = (await repo.count()).count;
diff --git a/backend/src/graphql-types/user.ts b/backend/src/graphql-types/user.ts
index 33e27fe..b208c58 100644
--- a/backend/src/graphql-types/user.ts
+++ b/backend/src/graphql-types/user.ts
@@ -1,5 +1,6 @@
 import { User } from '../models';
-import { field, objectType } from '@loopback/graphql';
+import { field, Int, objectType } from '@loopback/graphql';
+import { ListResponse } from './list';
 
 @objectType()
 export class UserResult implements Pick<User, 'id' | 'email' | 'name' | 'isAdmin'> {
@@ -21,6 +22,14 @@ export class LoginResult {
     user: UserResult;
 }
 
+@objectType()
+export class UserList implements ListResponse<UserResult> {
+    @field(returns => Int)
+    count: number;
+    @field(returns => [UserResult])
+    list: UserResult[];
+}
+
 export const UserProperties = {
     id: {
         type: 'number',
diff --git a/frontend/src/app/app.component.ts b/frontend/src/app/app.component.ts
index f1e3d01..3ca12ba 100644
--- a/frontend/src/app/app.component.ts
+++ b/frontend/src/app/app.component.ts
@@ -4,7 +4,6 @@ import { Observable } from 'rxjs';
 import { filter, map, shareReplay } from 'rxjs/operators';
 import { LoginService } from './auth/login.service';
 import { ActivatedRoute, ActivatedRouteSnapshot, NavigationEnd, Route, Router, Routes } from '@angular/router';
-import { ApiService } from './services/api.service';
 import { RouteData } from './app-routing.module';
 import { Title } from '@angular/platform-browser';
 
@@ -26,13 +25,11 @@ export class AppComponent implements OnInit {
     {path: 'subjects', requiredRole: 'admin'}
   ];
 
-  routeSegments: RouteSegment[];
-
   pageTitle: string;
 
   private activeRouteTitle: string;
 
-  constructor(private breakpointObserver: BreakpointObserver, public loginService: LoginService, private api: ApiService,
+  constructor(private breakpointObserver: BreakpointObserver, public loginService: LoginService,
               private router: Router, private activeRoute: ActivatedRoute, private title: Title) {
   }
 
diff --git a/frontend/src/app/graphql.module.ts b/frontend/src/app/graphql.module.ts
index 816f185..7f9b7e2 100644
--- a/frontend/src/app/graphql.module.ts
+++ b/frontend/src/app/graphql.module.ts
@@ -1,13 +1,51 @@
-import { NgModule } from '@angular/core';
+import { Injector, NgModule } from '@angular/core';
 import { APOLLO_OPTIONS } from 'apollo-angular';
-import { ApolloClientOptions, InMemoryCache } from '@apollo/client/core';
+import { ApolloClientOptions, ApolloLink, InMemoryCache } from '@apollo/client/core';
 import { HttpLink } from 'apollo-angular/http';
 import { environment } from '../environments/environment';
+import { setContext } from '@apollo/client/link/context';
+import { onError } from '@apollo/client/link/error';
+import { Router } from '@angular/router';
+import { LoginService } from './auth/login.service';
 
 const uri = environment.backendUrl + '/graphql'; // <-- add the URL of the GraphQL server here
-export function createApollo(httpLink: HttpLink): ApolloClientOptions<any> {
+export function createApollo(httpLink: HttpLink, routerService: Router, injector: Injector): ApolloClientOptions<any> {
+  const auth = setContext((operation, context) => {
+    const token = injector.get(LoginService).token;
+
+    if (token === null) {
+      return {};
+    } else {
+      return {
+        headers: {
+          Authorization: `Bearer ${token}`
+        }
+      };
+    }
+  });
+
+  const errorLink = onError(({graphQLErrors, networkError}) => {
+    if (graphQLErrors) {
+      graphQLErrors.map((graphqlError) => {
+        console.log(graphqlError);
+        if (graphqlError.message.startsWith('Error verifying token')) {
+          injector.get(LoginService).deleteToken();
+          routerService.navigateByUrl('/');
+        } else {
+          alert(graphqlError.message);
+        }
+      });
+    }
+
+    if (networkError) {
+      const errorMessage = networkError.message;
+      console.log(errorMessage);
+      alert(errorMessage);
+    }
+  });
+
   return {
-    link: httpLink.create({uri}),
+    link: ApolloLink.from([auth, errorLink, httpLink.create({uri})]),
     cache: new InMemoryCache(),
   };
 }
@@ -17,7 +55,7 @@ export function createApollo(httpLink: HttpLink): ApolloClientOptions<any> {
     {
       provide: APOLLO_OPTIONS,
       useFactory: createApollo,
-      deps: [HttpLink],
+      deps: [HttpLink, Router, Injector],
     },
   ],
 })
diff --git a/frontend/src/app/graphql/subject.graphql b/frontend/src/app/graphql/subject.graphql
index 9e661f2..3af3f0b 100644
--- a/frontend/src/app/graphql/subject.graphql
+++ b/frontend/src/app/graphql/subject.graphql
@@ -16,3 +16,7 @@ query Subject($id: ID!) {
     description
   }
 }
+
+mutation EditSubject($input: SubjectUpdateInput!) {
+  subjectUpdate(subject: $input)
+}
diff --git a/frontend/src/app/graphql/user.graphql b/frontend/src/app/graphql/user.graphql
index 0b4f7e9..608fae3 100644
--- a/frontend/src/app/graphql/user.graphql
+++ b/frontend/src/app/graphql/user.graphql
@@ -13,3 +13,25 @@ mutation Login($email: String!, $password: String!) {
 mutation Logout {
   logout
 }
+
+query UserList($limit: Int!, $offset: Int!) {
+  users(limit: $limit, offset: $offset) {
+    id
+    name
+    email
+    isAdmin
+  }
+}
+
+query User($id: ID!) {
+  user(id: $id) {
+    id
+    isAdmin
+    email
+    name
+  }
+}
+
+mutation EditUser($input: UserUpdateInput!) {
+  userUpdate(user: $input)
+}
diff --git a/frontend/src/app/services/api.service.spec.ts b/frontend/src/app/services/api.service.spec.ts
deleted file mode 100644
index c0310ae..0000000
--- a/frontend/src/app/services/api.service.spec.ts
+++ /dev/null
@@ -1,16 +0,0 @@
-import { TestBed } from '@angular/core/testing';
-
-import { ApiService } from './api.service';
-
-describe('ApiService', () => {
-  let service: ApiService;
-
-  beforeEach(() => {
-    TestBed.configureTestingModule({});
-    service = TestBed.inject(ApiService);
-  });
-
-  it('should be created', () => {
-    expect(service).toBeTruthy();
-  });
-});
diff --git a/frontend/src/app/services/api.service.ts b/frontend/src/app/services/api.service.ts
deleted file mode 100644
index f520e2c..0000000
--- a/frontend/src/app/services/api.service.ts
+++ /dev/null
@@ -1,45 +0,0 @@
-import { Injectable } from '@angular/core';
-import { LoginService } from '../auth/login.service';
-import { Router } from '@angular/router';
-import { Apollo } from 'apollo-angular';
-import { gql } from '@apollo/client';
-
-@Injectable({
-  providedIn: 'root'
-})
-export class ApiService {
-
-  constructor(private apollo: Apollo, private loginService: LoginService, private router: Router) {
-  }
-
-  request(method: 'post' | 'get' | 'delete' | 'patch', url: string, body: any): Promise<any> {
-    const asd = this.apollo.query({
-      query: gql`
-        {
-          __typename
-        }
-      `
-      // headers: {Authorization: 'Bearer ' + this.loginService.token}
-    }).toPromise().then(res => res);
-    return asd.catch(e => {
-      if (e.status === 401) {
-        this.loginService.deleteToken();
-        return this.router.navigateByUrl('/auth/login');
-      } else {
-        throw e;
-      }
-    });
-  }
-
-  requestPage<T>(url: string, limit: number, page: number): Promise<T[]> {
-    const c = url.indexOf('?') === -1 ? '?' : '&';
-    return this.request('get', url + c + 'filter=' + encodeURI(JSON.stringify({
-      limit,
-      offset: (page - 1) * limit
-    })), {});
-  }
-
-  requestItemCount(url: string): Promise<number> {
-    return this.request('get', url + '/count', {}).then(count => count.count);
-  }
-}
diff --git a/frontend/src/app/shared-components/edit/edit.component.ts b/frontend/src/app/shared-components/edit/edit.component.ts
index b093211..2bb911f 100644
--- a/frontend/src/app/shared-components/edit/edit.component.ts
+++ b/frontend/src/app/shared-components/edit/edit.component.ts
@@ -1,21 +1,25 @@
 import { Component, Input, OnInit } from '@angular/core';
-import { ApiService } from '../../services/api.service';
 import { ActivatedRoute, Router } from '@angular/router';
 import { FormBuilder, FormControl, FormGroup } from '@angular/forms';
-import { Query } from 'apollo-angular';
+import { Mutation, Query } from 'apollo-angular';
+import { noop } from 'rxjs';
+import { HasID, MutationInput, QueryResult } from '../../utility/types';
 
 @Component({
   selector: 'app-edit',
   templateUrl: './edit.component.html',
   styleUrls: ['./edit.component.css']
 })
-export class EditComponent<T extends { id: number }, U> implements OnInit {
+export class EditComponent<T extends HasID, QT extends QueryResult<T>, UT extends QueryResult<T>, CT extends QueryResult<T>, MI extends Partial<T>>
+  implements OnInit {
 
   item?: T;
   creating = false;
   isLoading = true;
 
-  @Input() gql: Query<U, {}>;
+  @Input() gql: Query<QT, HasID>;
+  @Input() updateMutation: Mutation<UT, MutationInput<MI, T>>;
+  @Input() createMutation: Mutation<CT, MutationInput<MI, T>>;
   @Input() fields: { title: string, name: keyof T, readonly?: (item: T) => boolean }[];
   @Input() itemType: T;
   /**
@@ -24,15 +28,20 @@ export class EditComponent<T extends { id: number }, U> implements OnInit {
   @Input() beforeSubmit: (item: T) => Partial<T>;
   formGroup: FormGroup;
 
-  constructor(private api: ApiService, private router: Router, private fb: FormBuilder, private route: ActivatedRoute) {
+  private key: string;
+  private id: string;
+
+  constructor(private router: Router, private fb: FormBuilder, private route: ActivatedRoute) {
   }
 
   async ngOnInit(): Promise<void> {
-    this.item = JSON.parse(window.localStorage.getItem(this.router.url));
     window.localStorage.removeItem(this.router.url);
     const url = this.route.snapshot.url;
+    this.id = this.route.snapshot.url[this.route.snapshot.url.length - 1] + '';
     if (!this.item && url[url.length - 1].path !== 'new') {
-      //this.item = await this.api.request('get', this.apiPath + '/' + this.route.snapshot.url[this.route.snapshot.url.length - 1], {}); - TODO
+      const data = (await this.gql.fetch({id: this.id}).toPromise()).data;
+      this.key = Object.keys(data).filter(k => k !== '__typename')[0];
+      this.item = data[this.key];
     }
     this.formGroup = this.fb.group(this.fields.reduce((pv, cv) => {
       const control = new FormControl();
@@ -52,17 +61,17 @@ export class EditComponent<T extends { id: number }, U> implements OnInit {
 
   async submit(): Promise<void> {
     this.isLoading = true;
-    const value = Object.assign({}, this.formGroup.value, this.beforeSubmit(this.item) ?? {});
+    const input = Object.assign({}, this.formGroup.value, (this.beforeSubmit ?? noop)(this.item) ?? {}, {id: this.id}) as MI;
     try {
       if (this.item && !this.creating) {
-        //await this.api.request('patch', this.apiPath + '/' + this.item.id, value); - TODO
+        await this.updateMutation.mutate({input}).toPromise();
       } else {
-        //await this.api.request('post', this.apiPath, value); - TODO
+        await this.createMutation.mutate({input}).toPromise();
       }
       await this.router.navigate(['..'], {relativeTo: this.route});
     } catch (e) {
       alert(e.message);
-    }
+    } // TODO: Clear/update cache
     this.isLoading = false;
   }
 
diff --git a/frontend/src/app/shared-components/list/list.component.ts b/frontend/src/app/shared-components/list/list.component.ts
index 076d570..f5830fa 100644
--- a/frontend/src/app/shared-components/list/list.component.ts
+++ b/frontend/src/app/shared-components/list/list.component.ts
@@ -1,7 +1,6 @@
 import { Component, Input, OnInit } from '@angular/core';
 import { PageEvent } from '@angular/material/paginator';
 import { PaginationData } from '../../utility/pagination-data';
-import { ApiService } from '../../services/api.service';
 import { Router } from '@angular/router';
 import { Query } from 'apollo-angular';
 
@@ -23,7 +22,7 @@ export class ListComponent<T extends { id: number }, U extends { [entityName: st
   items: T[] = [];
   loading = false;
 
-  constructor(private api: ApiService, private router: Router) {
+  constructor(private router: Router) {
   }
 
   ngOnInit(): void {
diff --git a/frontend/src/app/subjects/subject-edit/subject-edit.component.html b/frontend/src/app/subjects/subject-edit/subject-edit.component.html
index 6fb21a5..a5c1341 100644
--- a/frontend/src/app/subjects/subject-edit/subject-edit.component.html
+++ b/frontend/src/app/subjects/subject-edit/subject-edit.component.html
@@ -1,4 +1,4 @@
 <app-edit [gql]="itemGQL" [itemType]="itemType" [fields]="[
   {title: 'Név', name: 'name'},
   {title: 'Leirás', name: 'description'}
-]"></app-edit>
+]" [updateMutation]="updateGQL"></app-edit>
diff --git a/frontend/src/app/subjects/subject-edit/subject-edit.component.ts b/frontend/src/app/subjects/subject-edit/subject-edit.component.ts
index 218035b..4cd8402 100644
--- a/frontend/src/app/subjects/subject-edit/subject-edit.component.ts
+++ b/frontend/src/app/subjects/subject-edit/subject-edit.component.ts
@@ -1,5 +1,5 @@
 import { Component, OnInit } from '@angular/core';
-import { Subject, SubjectGQL } from '../../services/graphql';
+import { EditSubjectGQL, Subject, SubjectGQL } from '../../services/graphql';
 
 @Component({
   selector: 'app-subject-edit',
@@ -9,7 +9,7 @@ import { Subject, SubjectGQL } from '../../services/graphql';
 export class SubjectEditComponent implements OnInit {
   itemType: Subject;
 
-  constructor(public itemGQL: SubjectGQL) {
+  constructor(public itemGQL: SubjectGQL, public updateGQL: EditSubjectGQL) {
   }
 
   ngOnInit(): void {
diff --git a/frontend/src/app/users/user-edit/user-edit.component.html b/frontend/src/app/users/user-edit/user-edit.component.html
index d019870..6f513f1 100644
--- a/frontend/src/app/users/user-edit/user-edit.component.html
+++ b/frontend/src/app/users/user-edit/user-edit.component.html
@@ -1,4 +1,4 @@
-<app-edit [itemType]="itemType" [fields]="[
+<app-edit [itemType]="itemType" [gql]="itemGQL" [updateMutation]="updateGQL" [fields]="[
   {title: 'E-mail', name: 'email'},
   {title: 'Név', name: 'name'},
   {title: 'Admin', name: 'isAdmin', readonly: isEditingSelf}
diff --git a/frontend/src/app/users/user-edit/user-edit.component.ts b/frontend/src/app/users/user-edit/user-edit.component.ts
index 8d4ee98..6a9431e 100644
--- a/frontend/src/app/users/user-edit/user-edit.component.ts
+++ b/frontend/src/app/users/user-edit/user-edit.component.ts
@@ -1,6 +1,6 @@
 import { Component, OnInit } from '@angular/core';
 import { LoginService } from '../../auth/login.service';
-import { UserResult } from '../../services/graphql';
+import { EditUserGQL, UserGQL, UserResult } from '../../services/graphql';
 
 @Component({
   selector: 'app-user-edit',
@@ -11,7 +11,8 @@ export class UserEditComponent implements OnInit {
   itemType: UserResult;
   isEditingSelf = user => user.id === this.userService.user.id;
 
-  constructor(private userService: LoginService) { }
+  constructor(private userService: LoginService, public itemGQL: UserGQL, public updateGQL: EditUserGQL) {
+  }
 
   ngOnInit(): void {
   }
diff --git a/frontend/src/app/users/user-list/user-list.component.html b/frontend/src/app/users/user-list/user-list.component.html
index d855457..ee81928 100644
--- a/frontend/src/app/users/user-list/user-list.component.html
+++ b/frontend/src/app/users/user-list/user-list.component.html
@@ -1,4 +1,4 @@
-<app-list apiPath="/users" [itemType]="itemType" [columns]="[
+<app-list [itemType]="itemType" [gql]="listGQL" [columns]="[
     {title: 'Név', prop: 'name'},
     {title: 'Admin', prop: 'isAdmin'}
   ]"></app-list>
diff --git a/frontend/src/app/users/user-list/user-list.component.ts b/frontend/src/app/users/user-list/user-list.component.ts
index cd94404..7837a76 100644
--- a/frontend/src/app/users/user-list/user-list.component.ts
+++ b/frontend/src/app/users/user-list/user-list.component.ts
@@ -1,5 +1,5 @@
 import { Component, OnInit } from '@angular/core';
-import { UserResult } from '../../services/graphql';
+import { UserListGQL, UserResult } from '../../services/graphql';
 
 @Component({
   selector: 'app-user-list',
@@ -9,7 +9,7 @@ import { UserResult } from '../../services/graphql';
 export class UserListComponent implements OnInit {
   itemType: UserResult;
 
-  constructor() {
+  constructor(public listGQL: UserListGQL) {
   }
 
   ngOnInit(): void {
diff --git a/frontend/src/app/utility/types.ts b/frontend/src/app/utility/types.ts
new file mode 100644
index 0000000..eeae322
--- /dev/null
+++ b/frontend/src/app/utility/types.ts
@@ -0,0 +1,5 @@
+import { Scalars } from '../services/graphql';
+
+export type HasID = { id: Scalars['ID'] };
+export type QueryResult<T extends HasID> = { [entityName: string]: T };
+export type MutationInput<T extends Partial<U>, U extends HasID> = { input: T };