diff --git a/BetterIServ.Backend/Controllers/StorageController.cs b/BetterIServ.Backend/Controllers/StorageController.cs
new file mode 100644
index 0000000..dbc4716
--- /dev/null
+++ b/BetterIServ.Backend/Controllers/StorageController.cs
@@ -0,0 +1,42 @@
+using System.Dynamic;
+using System.Text;
+using BetterIServ.Backend.Entities;
+using Microsoft.AspNetCore.Mvc;
+using Newtonsoft.Json;
+
+namespace BetterIServ.Backend.Controllers; 
+
+[ApiController]
+[Route("storage")]
+public class StorageController : ControllerBase {
+
+    [HttpPost]
+    public async Task<IActionResult> SetItem([FromQuery] string item, [FromQuery] string user) {
+        var data = await new StreamReader(Request.Body).ReadToEndAsync();
+        var file = new FileInfo($"/data/{user}/{item}.json");
+        
+        if (file.Directory?.Exists != true) file.Directory?.Create();
+
+        await using var stream = file.Exists ? file.OpenWrite() : file.Create();
+        await stream.WriteAsync(Encoding.UTF8.GetBytes(data));
+        return Ok();
+    }
+
+    [HttpGet]
+    public async Task<ActionResult<SingleResult<dynamic>>> GetItem([FromQuery] string item, [FromQuery] string user) {
+        var file = new FileInfo($"/data/{user}/{item}.json");
+        if (!file.Exists) return NotFound();
+
+        await using var stream = file.OpenRead();
+        var data = await new StreamReader(stream).ReadToEndAsync();
+        return Ok(new SingleResult<string>{Value = data});
+    }
+
+    [HttpDelete]
+    public IActionResult Clear([FromQuery] string user) {
+        if (!Directory.Exists($"/data/{user}")) return NotFound();
+        Directory.Delete($"/data/{user}", true);
+        return Ok();
+    }
+
+}
\ No newline at end of file
diff --git a/BetterIServ.Mobile/src/app/api/iserv.service.ts b/BetterIServ.Mobile/src/app/api/iserv.service.ts
index 3806f91..91ae8fb 100644
--- a/BetterIServ.Mobile/src/app/api/iserv.service.ts
+++ b/BetterIServ.Mobile/src/app/api/iserv.service.ts
@@ -4,16 +4,21 @@ import {Userdata, AuthKeys} from "../entities/userdata";
 import {firstValueFrom} from "rxjs";
 import {environment} from "../../environments/environment";
 import {Course} from "../entities/course";
+import {StorageService} from "./storage.service";
 
 @Injectable({
   providedIn: 'root',
 })
 export class IServService {
 
-  public userdata?: Userdata;
+  public static userdata?: Userdata;
   public keys?: AuthKeys;
   public backend: string = environment.backend;
 
+  public get userdata(): Userdata {
+    return IServService.userdata;
+  }
+
   public courseNames: {[id: string]: string} = {
     ["Bi"]: "Biologie",
     ["Ch"]: "Chemie",
@@ -43,10 +48,10 @@ export class IServService {
     {name: "Rot", val: "danger"}
   ];
 
-  constructor(private client: HttpClient) {
+  constructor(private client: HttpClient, private storage: StorageService) {
     const data = localStorage.getItem("userdata");
     if (data != null) {
-      this.userdata = JSON.parse(data);
+      IServService.userdata = JSON.parse(data);
     }
 
     const keys = localStorage.getItem("keys");
@@ -57,15 +62,15 @@ export class IServService {
 
   public async login(email: string, password: string): Promise<boolean> {
     const split = email.split('@');
-    this.userdata = {
+    IServService.userdata = {
       username: split[0],
       domain: split[1],
       password
     };
 
     try {
-      const keys = await firstValueFrom(this.client.post<AuthKeys>(this.backend + "/iserv/login", this.userdata));
-      localStorage.setItem("userdata", JSON.stringify(this.userdata));
+      const keys = await firstValueFrom(this.client.post<AuthKeys>(this.backend + "/iserv/login", IServService.userdata));
+      localStorage.setItem("userdata", JSON.stringify(IServService.userdata));
       localStorage.setItem("keys", JSON.stringify(keys));
       return true;
     }catch (error) {
@@ -74,31 +79,29 @@ export class IServService {
   }
 
   public logout() {
-    delete this.userdata;
+    delete IServService.userdata;
     delete this.keys;
   }
 
   public async getKeys(): Promise<AuthKeys> {
-    const keys = await firstValueFrom(this.client.post<AuthKeys>(this.backend + "/iserv/login", this.userdata));
+    const keys = await firstValueFrom(this.client.post<AuthKeys>(this.backend + "/iserv/login", IServService.userdata));
     localStorage.setItem("keys", JSON.stringify(keys));
     return keys;
   }
 
   public async getGroups(): Promise<string[]> {
     try {
-      return (await firstValueFrom(this.client.post<{value: string[]}>(this.backend + "/iserv/groups?domain=" + this.userdata.domain, this.keys))).value;
+      return (await firstValueFrom(this.client.post<{value: string[]}>(this.backend + "/iserv/groups?domain=" + IServService.userdata.domain, this.keys))).value;
     } catch {
       const keys = await this.getKeys();
-      return (await firstValueFrom(this.client.post<{value: string[]}>(this.backend + "/iserv/groups?domain=" + this.userdata.domain, keys))).value;
+      return (await firstValueFrom(this.client.post<{value: string[]}>(this.backend + "/iserv/groups?domain=" + IServService.userdata.domain, keys))).value;
     }
   }
 
   public async getCoursesAndClass(groups?: string[]): Promise<{class: string, courses: Course[]}> {
-    if (localStorage.getItem("courses") && localStorage.getItem("class")) {
-      const courses = JSON.parse(localStorage.getItem("courses")) as Course[];
-      const className = localStorage.getItem("class");
-      return {courses, class: className};
-    }
+    const courses = await this.storage.getItem<Course[]>("courses");
+    const className = await this.storage.getItem<string>("class", false);
+    if (courses != undefined && className != undefined) return {class: className, courses};
 
     if (groups == undefined) {
       groups = await this.getGroups();
@@ -115,7 +118,7 @@ export class IServService {
         result.class = grades[0].replace("Jahrgang ", "").toUpperCase();
       }
     }
-    localStorage.setItem("class", result.class);
+    await this.storage.setItem("class", result.class);
 
     for (let group of groups) {
       if (!group.includes(".") || !group.toLowerCase().startsWith("q")) continue;
@@ -141,7 +144,7 @@ export class IServService {
         return 0;
       });
 
-      localStorage.setItem("courses", JSON.stringify(courses));
+      await this.storage.setItem("courses", JSON.stringify(courses));
       return {class: result.class, courses};
     }
 
diff --git a/BetterIServ.Mobile/src/app/api/storage.service.ts b/BetterIServ.Mobile/src/app/api/storage.service.ts
new file mode 100644
index 0000000..0034df1
--- /dev/null
+++ b/BetterIServ.Mobile/src/app/api/storage.service.ts
@@ -0,0 +1,33 @@
+import { Injectable } from '@angular/core';
+import {HttpClient} from "@angular/common/http";
+import {firstValueFrom} from "rxjs";
+import {environment} from "../../environments/environment";
+import {IServService} from "./iserv.service";
+
+@Injectable({
+  providedIn: 'root'
+})
+export class StorageService {
+
+  constructor(private client: HttpClient) {}
+
+  public async getItem<T>(item: string, isJson: boolean = true): Promise<T> {
+    try {
+      const data = await firstValueFrom(this.client.get<{value: string}>(environment.backend + `/storage?user=${IServService.userdata.username}&item=${item}`));
+
+      if (isJson) return JSON.parse(data.value) as T;
+      return data.value as T;
+    }catch {
+      return undefined;
+    }
+  }
+
+  public async setItem(item: string, value: any) {
+    await firstValueFrom(this.client.post(environment.backend + `/storage?user=${IServService.userdata.username}&item=${item}`, value));
+  }
+
+  public async clear() {
+    await firstValueFrom(this.client.delete(environment.backend + `/storage?user=${IServService.userdata.username}`));
+  }
+
+}
diff --git a/BetterIServ.Mobile/src/app/app.component.ts b/BetterIServ.Mobile/src/app/app.component.ts
index 32c561f..3592e5b 100644
--- a/BetterIServ.Mobile/src/app/app.component.ts
+++ b/BetterIServ.Mobile/src/app/app.component.ts
@@ -3,6 +3,7 @@ import { Component } from '@angular/core';
 import {Router, RouterLink, RouterLinkActive} from '@angular/router';
 import { IonicModule } from '@ionic/angular';
 import {IServService} from "./api/iserv.service";
+import {StorageService} from "./api/storage.service";
 @Component({
   selector: 'app-root',
   templateUrl: 'app.component.html',
@@ -20,16 +21,16 @@ export class AppComponent {
     { title: 'Vertretungsplan', url: '/substitution', icon: 'list' },
   ];
 
-  constructor(public router: Router, public iserv: IServService) {
+  constructor(public router: Router, public iserv: IServService, private storage: StorageService) {
     if (localStorage.getItem("userdata") == null) {
       this.router.navigate(["login"]);
     }
   }
 
-  public logout() {
-    localStorage.clear();
+  public async logout() {
+    await this.storage.clear();
     this.iserv.logout();
-    this.router.navigate(["login"]);
+    await this.router.navigate(["login"]);
   }
 
 }
diff --git a/BetterIServ.Mobile/src/app/pages/home/home.page.html b/BetterIServ.Mobile/src/app/pages/home/home.page.html
index 8fecdb3..843dd81 100644
--- a/BetterIServ.Mobile/src/app/pages/home/home.page.html
+++ b/BetterIServ.Mobile/src/app/pages/home/home.page.html
@@ -30,7 +30,7 @@
       <ion-card-title>Stundenplan</ion-card-title>
     </ion-card-header>
     <ion-card-content class="lesson-content">
-      <ion-card *ngIf="lessons == undefined">
+      <ion-card *ngIf="lessons?.length < 1">
         <ion-card-header>
           <ion-card-subtitle>Kein Unterricht</ion-card-subtitle>
         </ion-card-header>
@@ -48,7 +48,7 @@
       <ion-card-subtitle>{{subsDate?.toLocaleDateString()}}</ion-card-subtitle>
     </ion-card-header>
     <ion-card-content>
-      <ion-card *ngIf="subs?.length == 0 && subs != undefined">
+      <ion-card *ngIf="subs?.length < 1">
         <ion-card-header>
           <ion-card-subtitle>Keine Vertretungen</ion-card-subtitle>
         </ion-card-header>
@@ -64,7 +64,7 @@
     </ion-card-header>
     <ion-card-content>
       <ion-list>
-        <ion-card *ngIf="unreadMails?.length == 0">
+        <ion-card *ngIf="unreadMails?.length < 1">
           <ion-card-header>
             <ion-card-subtitle>Keine ungelesenen E-Mails</ion-card-subtitle>
           </ion-card-header>
diff --git a/BetterIServ.Mobile/src/app/pages/home/home.page.ts b/BetterIServ.Mobile/src/app/pages/home/home.page.ts
index e5ba027..cc6708c 100644
--- a/BetterIServ.Mobile/src/app/pages/home/home.page.ts
+++ b/BetterIServ.Mobile/src/app/pages/home/home.page.ts
@@ -1,5 +1,5 @@
 import {Component, OnInit} from '@angular/core';
-import { CommonModule } from '@angular/common';
+import {CommonModule, Time} from '@angular/common';
 import { FormsModule } from '@angular/forms';
 import { IonicModule } from '@ionic/angular';
 import {IServService} from "../../api/iserv.service";
@@ -12,6 +12,7 @@ import {MailComponent} from "../../components/mail/mail.component";
 import {Router} from "@angular/router";
 import {Course, Lesson, Timetable} from "../../entities/course";
 import {LessonComponent} from "../../components/lesson/lesson.component";
+import {StorageService} from "../../api/storage.service";
 
 @Component({
   selector: 'app-home',
@@ -30,7 +31,7 @@ export class HomePage implements OnInit {
   public classData: {class: string, courses: Course[]};
   public lessons: Lesson[];
 
-  public constructor(public iserv: IServService, public mails: MailService, public units: UnitsService, public router: Router) {}
+  public constructor(public iserv: IServService, public mails: MailService, public units: UnitsService, public router: Router, private storage: StorageService) {}
 
   async ngOnInit() {
     this.today = new Date();
@@ -40,11 +41,17 @@ export class HomePage implements OnInit {
     const mailPromise = this.mails.getMails("INBOX", 0);
     const classPromise = this.iserv.getCoursesAndClass();
     const subsPromise = this.units.getSubstitutionPlan("today");
-    await Promise.all([mailPromise, classPromise, subsPromise]);
+    const timetablePromise = this.storage.getItem<Timetable>("timetable");
+    await Promise.all([mailPromise, classPromise, subsPromise, timetablePromise]);
 
     this.unreadMails = (await mailPromise).filter(mail => !mail.read);
     this.classData = await classPromise;
     let unitsData = await subsPromise;
+    const timetable = await timetablePromise;
+
+    if (scheduleDay != undefined && timetable != undefined) {
+      this.lessons = timetable[scheduleDay].filter(lesson => lesson != undefined);
+    }
 
     if (this.dateIsPast(unitsData.date, new Date())) {
       unitsData = await this.units.getSubstitutionPlan("tomorrow");
@@ -55,10 +62,6 @@ export class HomePage implements OnInit {
     if (this.classData.class.startsWith("Q")) {
       this.subs = this.subs.filter(subs => this.classData.courses.filter(course => course.id == subs.lesson).length > 0);
     }
-
-    if (scheduleDay != undefined && localStorage.getItem("timetable")) {
-      this.lessons = (JSON.parse(localStorage.getItem("timetable")) as Timetable)[scheduleDay].filter(lesson => lesson != undefined);
-    }
   }
 
   private dateIsPast(first: Date, second: Date): boolean {
diff --git a/BetterIServ.Mobile/src/app/pages/schedule/schedule.page.ts b/BetterIServ.Mobile/src/app/pages/schedule/schedule.page.ts
index ec78eee..d528a74 100644
--- a/BetterIServ.Mobile/src/app/pages/schedule/schedule.page.ts
+++ b/BetterIServ.Mobile/src/app/pages/schedule/schedule.page.ts
@@ -6,6 +6,7 @@ import {IServService} from "../../api/iserv.service";
 import {Course, Lesson, Timetable} from "../../entities/course";
 import {WeekPipe} from "../../pipes/week.pipe";
 import {LessonComponent} from "../../components/lesson/lesson.component";
+import {StorageService} from "../../api/storage.service";
 
 @Component({
   selector: 'app-schedule',
@@ -26,20 +27,19 @@ export class SchedulePage implements OnInit {
   @ViewChild('courseModal') courseModal: IonModal;
   @ViewChild('tableModal') tableModal: IonModal;
 
-  constructor(public iserv: IServService) { }
+  constructor(public iserv: IServService, private storage: StorageService) { }
 
   async ngOnInit() {
     this.courses = (await this.iserv.getCoursesAndClass()).courses;
+    this.timetable = await this.storage.getItem("timetable");
 
-    if (localStorage.getItem("timetable") == undefined) {
+    if (this.timetable == undefined) {
       for (let day of ['mon', 'tue', 'wed', 'thu', 'fri']) {
         for (let i = 0; i < 10; i++) {
           this.timetable[day].push(undefined);
         }
       }
-      localStorage.setItem("timetable", JSON.stringify(this.timetable));
-    }else {
-      this.timetable = JSON.parse(localStorage.getItem("timetable"));
+      await this.storage.setItem("timetable", this.timetable);
     }
   }
 
@@ -71,7 +71,7 @@ export class SchedulePage implements OnInit {
       if (a.name > b.name) return 1;
       return 0;
     });
-    localStorage.setItem("courses", JSON.stringify(this.courses));
+    await this.storage.setItem("courses", JSON.stringify(this.courses));
   }
 
   public async updateOrCreateLesson(event: any) {
@@ -88,7 +88,7 @@ export class SchedulePage implements OnInit {
       this.timetable[data.day][data.time] = data.lesson;
     }
 
-    localStorage.setItem("timetable", JSON.stringify(this.timetable));
+    await this.storage.setItem("timetable", JSON.stringify(this.timetable));
     location.reload();
   }
 
@@ -120,11 +120,11 @@ export class SchedulePage implements OnInit {
     this.allCourses.push({short, name, id: short, color: this.getRandomColor()});
   }
 
-  public saveCourses(event: any) {
+  public async saveCourses(event: any) {
     if (event.detail.role != "confirm") return;
     this.courses = this.allCourses;
     delete this.allCourses;
-    localStorage.setItem("courses", JSON.stringify(this.courses));
+    await this.storage.setItem("courses", this.courses);
   }
 
 }
diff --git a/BetterIServ.Mobile/src/app/pages/substitution/substitution.page.ts b/BetterIServ.Mobile/src/app/pages/substitution/substitution.page.ts
index 3f6adcb..191828a 100644
--- a/BetterIServ.Mobile/src/app/pages/substitution/substitution.page.ts
+++ b/BetterIServ.Mobile/src/app/pages/substitution/substitution.page.ts
@@ -6,6 +6,7 @@ import {UnitsService} from "../../api/units.service";
 import {UnitsData} from "../../entities/substitution";
 import {IServService} from "../../api/iserv.service";
 import {SubstitutionComponent} from "../../components/substitution/substitution.component";
+import {StorageService} from "../../api/storage.service";
 
 @Component({
   selector: 'app-substitution',
@@ -22,12 +23,12 @@ export class SubstitutionPage implements OnInit {
   public currentClass: string;
   public filterByClasses: boolean = false;
 
-  constructor(public units: UnitsService, private iserv: IServService, private alerts: AlertController) {
-    this.currentClass = localStorage.getItem("class") || 'all';
-    this.filterByClasses = localStorage.getItem("filterByClasses") == "true";
-  }
+  constructor(public units: UnitsService, private iserv: IServService, private alerts: AlertController, private storage: StorageService) {}
 
   async ngOnInit() {
+    this.currentClass = await this.storage.getItem("class", false) || 'all';
+    this.filterByClasses = await this.storage.getItem("filterByClasses", false) == "true";
+
     if (!this.units.doesSchoolExist()) {
       const alert = await this.alerts.create({
         subHeader: "Fehler",
@@ -47,7 +48,7 @@ export class SubstitutionPage implements OnInit {
         this.courses.push(course.id);
       }
 
-      if (localStorage.getItem("filterByClasses") == null) {
+      if (await this.storage.getItem("filterByClasses") == undefined) {
         this.showOnlyCourses(true);
         this.filterByClasses = true;
 
@@ -69,14 +70,14 @@ export class SubstitutionPage implements OnInit {
 
   public changeClass(className: string) {
     this.currentClass = className;
-    localStorage.setItem("class", className);
+    this.storage.setItem("class", className);
 
     this.filterByClasses = false;
     this.showOnlyCourses(false);
   }
 
   public showOnlyCourses(toggle: boolean) {
-    localStorage.setItem("filterByClasses", toggle.toString());
+    this.storage.setItem("filterByClasses", toggle.toString());
   }
 
   public hasClass(course: string): boolean {
diff --git a/BetterIServ.Mobile/src/app/pipes/week.pipe.ts b/BetterIServ.Mobile/src/app/pipes/week.pipe.ts
index a779783..25ee661 100644
--- a/BetterIServ.Mobile/src/app/pipes/week.pipe.ts
+++ b/BetterIServ.Mobile/src/app/pipes/week.pipe.ts
@@ -8,6 +8,8 @@ import {Lesson} from "../entities/course";
 export class WeekPipe implements PipeTransform {
 
   transform(objects: Lesson[]): Lesson[] {
+    if (objects == undefined) return [];
+
     const week = this.getWeek(new Date()) % 2;
     const label = week == 0 ? "a" : "b";
     const result = [];