diff --git a/backend/.env.test b/backend/.env.test
index 535628cd..4444ec29 100644
--- a/backend/.env.test
+++ b/backend/.env.test
@@ -11,3 +11,10 @@ DWENGO_PORT=3000
 
 DWENGO_DB_NAME=":memory:"
 DWENGO_DB_UPDATE=true
+
+DWENGO_AUTH_STUDENT_URL=http://localhost:7080/realms/student
+DWENGO_AUTH_STUDENT_JWKS_ENDPOINT=http://localhost:7080/realms/student/protocol/openid-connect/certs
+DWENGO_AUTH_TEACHER_URL=http://localhost:7080/realms/teacher
+DWENGO_AUTH_TEACHER_JWKS_ENDPOINT=http://localhost:7080/realms/teacher/protocol/openid-connect/certs
+
+DWENGO_CORS_ALLOWED_ORIGINS=http://localhost:5173,http://localhost:3000
diff --git a/backend/package.json b/backend/package.json
index 275bad7d..ac5ebb48 100644
--- a/backend/package.json
+++ b/backend/package.json
@@ -7,7 +7,8 @@
     "main": "dist/app.js",
     "scripts": {
         "build": "cross-env NODE_ENV=production tsc --build",
-        "dev": "cross-env NODE_ENV=development tsx tool/seed.ts; tsx watch --env-file=.env.development.local src/app.ts",
+        "predev": "tsc --build ../common/tsconfig.json",
+        "dev": "cross-env NODE_ENV=development tsx tool/seed.ts && tsx watch --env-file=.env.development.local src/app.ts",
         "start": "cross-env NODE_ENV=production node --env-file=.env dist/app.js",
         "format": "prettier --write src/",
         "format-check": "prettier --check src/",
diff --git a/backend/src/controllers/groups.ts b/backend/src/controllers/groups.ts
index 53bc96ec..217510f6 100644
--- a/backend/src/controllers/groups.ts
+++ b/backend/src/controllers/groups.ts
@@ -3,8 +3,6 @@ import { createGroup, deleteGroup, getAllGroups, getGroup, getGroupSubmissions,
 import { GroupDTO } from '@dwengo-1/common/interfaces/group';
 import { requireFields } from './error-helper.js';
 import { BadRequestException } from '../exceptions/bad-request-exception.js';
-import { EntityDTO } from '@mikro-orm/core';
-import { Group } from '../entities/assignments/group.entity.js';
 
 function checkGroupFields(classId: string, assignmentId: number, groupId: number): void {
     requireFields({ classId, assignmentId, groupId });
@@ -35,7 +33,11 @@ export async function putGroupHandler(req: Request, res: Response): Promise<void
     const groupId = parseInt(req.params.groupid);
     checkGroupFields(classId, assignmentId, groupId);
 
-    const group = await putGroup(classId, assignmentId, groupId, req.body as Partial<EntityDTO<Group>>);
+    // Only members field can be changed
+    const members = req.body.members;
+    requireFields({ members });
+
+    const group = await putGroup(classId, assignmentId, groupId, { members } as Partial<GroupDTO>);
 
     res.json({ group });
 }
diff --git a/backend/src/logging/initalize.ts b/backend/src/logging/initalize.ts
index 5c94a25f..f89518c4 100644
--- a/backend/src/logging/initalize.ts
+++ b/backend/src/logging/initalize.ts
@@ -26,13 +26,15 @@ function initializeLogger(): Logger {
 
     const consoleTransport = new transports.Console({
         level: getEnvVar(envVars.LogLevel),
-        format: format.combine(format.cli(), format.colorize()),
+        format: format.combine(format.cli(), format.simple()),
     });
 
     if (getEnvVar(envVars.RunMode) === 'dev') {
-        return createLogger({
+        logger = createLogger({
             transports: [consoleTransport],
         });
+        logger.debug(`Logger initialized with level ${logLevel} to console`);
+        return logger;
     }
 
     const lokiHost = getEnvVar(envVars.LokiHost);
diff --git a/backend/src/logging/mikroOrmLogger.ts b/backend/src/logging/mikroOrmLogger.ts
index 9cb797a8..0fc18b87 100644
--- a/backend/src/logging/mikroOrmLogger.ts
+++ b/backend/src/logging/mikroOrmLogger.ts
@@ -11,7 +11,7 @@ export class MikroOrmLogger extends DefaultLogger {
         };
 
         let message: string;
-        if (context?.label) {
+        if (context !== undefined && context.labels !== undefined) {
             message = `[${namespace}] (${context.label}) ${messageArg}`;
         } else {
             message = `[${namespace}] ${messageArg}`;
diff --git a/backend/src/services/groups.ts b/backend/src/services/groups.ts
index 0c73c8c5..382780d8 100644
--- a/backend/src/services/groups.ts
+++ b/backend/src/services/groups.ts
@@ -7,8 +7,17 @@ import { GroupDTO, GroupDTOId } from '@dwengo-1/common/interfaces/group';
 import { SubmissionDTO, SubmissionDTOId } from '@dwengo-1/common/interfaces/submission';
 import { fetchAssignment } from './assignments.js';
 import { NotFoundException } from '../exceptions/not-found-exception.js';
-import { putObject } from './service-helper.js';
 import { fetchStudents } from './students.js';
+import { fetchClass } from './classes.js';
+import { BadRequestException } from '../exceptions/bad-request-exception.js';
+import { Student } from '../entities/users/student.entity.js';
+import { Class } from '../entities/classes/class.entity.js';
+
+async function assertMembersInClass(members: Student[], cls: Class): Promise<void> {
+    if (!members.every((student) => cls.students.contains(student))) {
+        throw new BadRequestException('Student does not belong to class');
+    }
+}
 
 export async function fetchGroup(classId: string, assignmentNumber: number, groupNumber: number): Promise<Group> {
     const assignment = await fetchAssignment(classId, assignmentNumber);
@@ -28,15 +37,18 @@ export async function getGroup(classId: string, assignmentNumber: number, groupN
     return mapToGroupDTO(group, group.assignment.within);
 }
 
-export async function putGroup(
-    classId: string,
-    assignmentNumber: number,
-    groupNumber: number,
-    groupData: Partial<EntityDTO<Group>>
-): Promise<GroupDTO> {
+export async function putGroup(classId: string, assignmentNumber: number, groupNumber: number, groupData: Partial<GroupDTO>): Promise<GroupDTO> {
     const group = await fetchGroup(classId, assignmentNumber, groupNumber);
 
-    await putObject<Group>(group, groupData, getGroupRepository());
+    const memberUsernames = groupData.members as string[];
+    const members = await fetchStudents(memberUsernames);
+
+    const cls = await fetchClass(classId);
+    await assertMembersInClass(members, cls);
+
+    const groupRepository = getGroupRepository();
+    groupRepository.assign(group, { members } as Partial<EntityDTO<Group>>);
+    await groupRepository.getEntityManager().persistAndFlush(group);
 
     return mapToGroupDTO(group, group.assignment.within);
 }
@@ -63,6 +75,9 @@ export async function createGroup(groupData: GroupDTO, classid: string, assignme
     const memberUsernames = (groupData.members as string[]) || [];
     const members = await fetchStudents(memberUsernames);
 
+    const cls = await fetchClass(classid);
+    await assertMembersInClass(members, cls);
+
     const assignment = await fetchAssignment(classid, assignmentNumber);
 
     const groupRepository = getGroupRepository();
diff --git a/backend/tests/test_assets/assignments/groups.testdata.ts b/backend/tests/test_assets/assignments/groups.testdata.ts
index 16674843..4361383b 100644
--- a/backend/tests/test_assets/assignments/groups.testdata.ts
+++ b/backend/tests/test_assets/assignments/groups.testdata.ts
@@ -61,7 +61,7 @@ export function makeTestGroups(em: EntityManager, students: Student[], assignmen
      */
     group1ConditionalLearningPath = em.create(Group, {
         assignment: getConditionalPathAssignment(),
-        groupNumber: 1,
+        groupNumber: 21005,
         members: [getTestleerling1()],
     });
 
diff --git a/backend/tool/seed.ts b/backend/tool/seed.ts
index 3cb4543c..00e3c0bf 100644
--- a/backend/tool/seed.ts
+++ b/backend/tool/seed.ts
@@ -14,14 +14,12 @@ import { makeTestQuestions } from '../tests/test_assets/questions/questions.test
 import { makeTestStudents } from '../tests/test_assets/users/students.testdata.js';
 import { makeTestTeachers } from '../tests/test_assets/users/teachers.testdata.js';
 import { getLogger, Logger } from '../src/logging/initalize.js';
-import { Collection } from '@mikro-orm/core';
+import { Collection, MikroORM } from '@mikro-orm/core';
 import { Group } from '../src/entities/assignments/group.entity';
 
 const logger: Logger = getLogger();
 
-export async function seedDatabase(): Promise<void> {
-    dotenv.config({ path: '.env.development.local' });
-    const orm = await initORM();
+export async function seedORM(orm: MikroORM): Promise<void> {
     await orm.schema.clearDatabase();
 
     const em = forkEntityManager();
@@ -68,8 +66,17 @@ export async function seedDatabase(): Promise<void> {
     ]);
 
     logger.info('Development database seeded successfully!');
+}
+
+export async function seedDatabase(envFile = '.env.development.local', testMode = false): Promise<void> {
+    dotenv.config({ path: envFile });
+    const orm = await initORM(testMode);
+
+    await seedORM(orm);
 
     await orm.close();
 }
 
-seedDatabase().catch(logger.error);
+seedDatabase().catch((err) => {
+    logger.error(err);
+});
diff --git a/backend/tool/startTestApp.ts b/backend/tool/startTestApp.ts
new file mode 100644
index 00000000..a5d0f852
--- /dev/null
+++ b/backend/tool/startTestApp.ts
@@ -0,0 +1,29 @@
+import express, { Express } from 'express';
+import { initORM } from '../src/orm.js';
+import apiRouter from '../src/routes/router.js';
+import { errorHandler } from '../src/middleware/error-handling/error-handler.js';
+import dotenv from 'dotenv';
+import cors from '../src/middleware/cors';
+import { authenticateUser } from '../src/middleware/auth/auth';
+import { seedORM } from './seed';
+
+const envFile = '../.env.test';
+
+dotenv.config({ path: envFile });
+
+const app: Express = express();
+
+app.use(express.json());
+app.use(cors);
+app.use(authenticateUser);
+
+app.use('/api', apiRouter);
+app.use(errorHandler);
+
+async function startServer(): Promise<void> {
+    await seedORM(await initORM(true));
+
+    app.listen(9876);
+}
+
+await startServer();
diff --git a/frontend/package.json b/frontend/package.json
index c5224a1a..cdd7dda1 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -10,14 +10,12 @@
         "preview": "vite preview",
         "type-check": "vue-tsc --build",
         "format": "prettier --write src/",
-        "test:e2e": "playwright test",
         "format-check": "prettier --check src/",
         "lint": "eslint . --fix",
-        "pretest:unit": "tsx ../docs/api/generate.ts && npm run build",
-        "test:unit": "vitest --run"
+        "test:unit": "vitest --run",
+        "test:e2e": "playwright test"
     },
     "dependencies": {
-        "@dwengo-1/common": "^0.1.1",
         "@tanstack/react-query": "^5.69.0",
         "@tanstack/vue-query": "^5.69.0",
         "axios": "^1.8.2",
diff --git a/frontend/src/App.vue b/frontend/src/App.vue
index b1207448..dbb62e79 100644
--- a/frontend/src/App.vue
+++ b/frontend/src/App.vue
@@ -3,6 +3,9 @@
     import MenuBar from "@/components/MenuBar.vue";
     import { useRoute } from "vue-router";
     import { computed } from "vue";
+    import authService from "@/services/auth/auth-service.ts";
+
+    void authService.loadUser();
 
     const route = useRoute();
     interface RouteMeta {
diff --git a/frontend/src/components/MenuBar.vue b/frontend/src/components/MenuBar.vue
index 0954707f..e3734976 100644
--- a/frontend/src/components/MenuBar.vue
+++ b/frontend/src/components/MenuBar.vue
@@ -11,7 +11,7 @@
     const { t, locale } = useI18n();
 
     const role = auth.authState.activeRole;
-    const router = useRouter();
+    const _router = useRouter(); // Zonder '_' gaf dit een linter error voor unused variable
 
     const name: string = auth.authState.user!.profile.name!;
     const initials: string = name
diff --git a/frontend/src/config.ts b/frontend/src/config.ts
index 53d6f253..cff1d771 100644
--- a/frontend/src/config.ts
+++ b/frontend/src/config.ts
@@ -1,8 +1,24 @@
 export const apiConfig = {
-    baseUrl:
-        window.location.hostname === "localhost" && !(window.location.port === "80" || window.location.port === "")
-            ? "http://localhost:3000/api"
-            : window.location.origin + "/api",
+    baseUrl: ((): string => {
+        if (import.meta.env.MODE === "test") {
+            // TODO Remove hardcoding
+            return "http://localhost:9876/api";
+        }
+
+        if (import.meta.env.VITE_API_BASE_URL) {
+            return import.meta.env.VITE_API_BASE_URL;
+        }
+
+        if (
+            window.location.hostname === "localhost" &&
+            !(window.location.port === "80" || window.location.port === "")
+        ) {
+            return "http://localhost:3000/api";
+        }
+
+        // Fallback to the current origin with "/api" suffix
+        return `${window.location.origin}/api`;
+    })(),
 };
 
 export const loginRoute = "/login";
diff --git a/frontend/src/controllers/base-controller.ts b/frontend/src/controllers/base-controller.ts
index 3d22e099..64f2363d 100644
--- a/frontend/src/controllers/base-controller.ts
+++ b/frontend/src/controllers/base-controller.ts
@@ -1,6 +1,7 @@
 import apiClient from "@/services/api-client/api-client.ts";
 import type { AxiosResponse, ResponseType } from "axios";
 import { HttpErrorResponseException } from "@/exception/http-error-response-exception.ts";
+import { apiConfig } from "@/config.ts";
 
 export abstract class BaseController {
     protected basePath: string;
@@ -16,9 +17,18 @@ export abstract class BaseController {
     }
 
     protected async get<T>(path: string, queryParams?: QueryParams, responseType?: ResponseType): Promise<T> {
-        const response = await apiClient.get<T>(this.absolutePathFor(path), { params: queryParams, responseType });
-        BaseController.assertSuccessResponse(response);
-        return response.data;
+        try {
+            const response = await apiClient.get<T>(this.absolutePathFor(path), { params: queryParams, responseType });
+            BaseController.assertSuccessResponse(response);
+            return response.data;
+        } catch (error) {
+            if (error instanceof HttpErrorResponseException) {
+                throw error;
+            }
+            throw new Error(
+                `An unexpected error occurred while fetching data from ${apiConfig.baseUrl}${this.absolutePathFor(path)}: ${error}`,
+            );
+        }
     }
 
     protected async post<T>(path: string, body: unknown, queryParams?: QueryParams): Promise<T> {
diff --git a/frontend/src/main.ts b/frontend/src/main.ts
index e4bdde40..b5315634 100644
--- a/frontend/src/main.ts
+++ b/frontend/src/main.ts
@@ -12,11 +12,9 @@ import App from "./App.vue";
 import router from "./router";
 import { aliases, mdi } from "vuetify/iconsets/mdi";
 import { VueQueryPlugin, QueryClient } from "@tanstack/vue-query";
-import authService from "./services/auth/auth-service.ts";
 
 const app = createApp(App);
 
-await authService.loadUser();
 app.use(router);
 
 const link = document.createElement("link");
diff --git a/frontend/src/router/index.ts b/frontend/src/router/index.ts
index 1eeb8865..8092ffd5 100644
--- a/frontend/src/router/index.ts
+++ b/frontend/src/router/index.ts
@@ -138,7 +138,7 @@ const router = createRouter({
 router.beforeEach(async (to, _from, next) => {
     // Verify if user is logged in before accessing certain routes
     if (to.meta.requiresAuth) {
-        if (!authService.isLoggedIn.value) {
+        if (!authService.isLoggedIn.value && !(await authService.loadUser())) {
             next("/login");
         } else {
             next();
diff --git a/frontend/src/services/auth/auth-service.ts b/frontend/src/services/auth/auth-service.ts
index 9151e0a9..a813cd6e 100644
--- a/frontend/src/services/auth/auth-service.ts
+++ b/frontend/src/services/auth/auth-service.ts
@@ -37,7 +37,20 @@ async function loadUser(): Promise<User | null> {
     if (!activeRole) {
         return null;
     }
-    const user = await (await getUserManagers())[activeRole].getUser();
+
+    const userManager = (await getUserManagers())[activeRole];
+    let user = await userManager.getUser(); // Load the user from the local storage.
+    if (!user) {
+        // If the user is not in the local storage, he could still be authenticated in Keycloak.
+        try {
+            user = await userManager.signinSilent();
+        } catch (_: unknown) {
+            // When the user was previously logged in and then logged out, signinSilent throws an error.
+            // In that case, the user is not authenticated anymore, so we set him to null.
+            user = null;
+        }
+    }
+
     setUserAuthInfo(user);
     authState.activeRole = activeRole ?? null;
     return user;
diff --git a/frontend/tests/controllers/student-controller.test.ts b/frontend/tests/controllers/student-controller.test.ts
new file mode 100644
index 00000000..89c8224e
--- /dev/null
+++ b/frontend/tests/controllers/student-controller.test.ts
@@ -0,0 +1,19 @@
+import { StudentController } from "../../src/controllers/students";
+import { expect, it, describe, afterAll, beforeAll } from "vitest";
+import { setup, teardown } from "../setup-backend.js";
+
+describe("Test controller students", () => {
+    beforeAll(async () => {
+        await setup();
+    });
+
+    afterAll(async () => {
+        await teardown();
+    });
+
+    it("Get students", async () => {
+        const controller = new StudentController();
+        const data = await controller.getAll(true);
+        expect(data.students).to.have.length.greaterThan(0);
+    });
+});
diff --git a/frontend/tests/setup-backend.ts b/frontend/tests/setup-backend.ts
new file mode 100644
index 00000000..6a0a256d
--- /dev/null
+++ b/frontend/tests/setup-backend.ts
@@ -0,0 +1,40 @@
+import { spawn } from "child_process";
+import { ChildProcess, spawnSync } from "node:child_process";
+
+let backendProcess: ChildProcess;
+
+async function waitForEndpoint(url: string, delay = 1000, retries = 60): Promise<void> {
+    try {
+        await fetch(url);
+    } catch {
+        // Endpoint is not ready yet
+        await new Promise((resolve) => setTimeout(resolve, delay));
+        // Retry
+        await waitForEndpoint(url, delay, retries - 1);
+    }
+}
+
+export async function setup(): Promise<void> {
+    // Precompile needed packages
+    spawnSync("npx", ["tsc", "--build", "tsconfig.json"], {
+        cwd: `../common`,
+    });
+
+    // Spin up the backend
+    backendProcess = spawn("npx", ["tsx", "--env-file=.env.test", "tool/startTestApp.ts"], {
+        cwd: `../backend`,
+        env: {
+            ...process.env,
+            NODE_ENV: "test",
+        },
+    });
+
+    // Wait until you can curl the backend
+    await waitForEndpoint("http://localhost:9876/api");
+}
+
+export async function teardown(): Promise<void> {
+    if (backendProcess) {
+        backendProcess.kill();
+    }
+}
diff --git a/frontend/vitest.config.ts b/frontend/vitest.config.ts
index ba2d72b6..51fc91ab 100644
--- a/frontend/vitest.config.ts
+++ b/frontend/vitest.config.ts
@@ -9,6 +9,13 @@ export default mergeConfig(
             environment: "jsdom",
             exclude: [...configDefaults.exclude, "e2e/**"],
             root: fileURLToPath(new URL("./", import.meta.url)),
+
+            /*
+             * The test-backend server can be started for each test-file individually using `beforeAll(() => setup())`,
+             * or for all tests once using:
+             globalSetup: ["./tests/setup-backend.ts"],
+             * In this project, the backend server is started for each test-file individually.
+             */
         },
     }),
 );