diff --git a/backend/src/controllers/students.ts b/backend/src/controllers/students.ts
index 4bc4394e..51488a2a 100644
--- a/backend/src/controllers/students.ts
+++ b/backend/src/controllers/students.ts
@@ -14,8 +14,8 @@ import {
     getStudentQuestions,
     getStudentSubmissions,
 } from '../services/students.js';
-import { StudentDTO } from '../interfaces/student.js';
 import { requireFields } from './error-helper.js';
+import { StudentDTO } from '@dwengo-1/common/interfaces/student';
 
 export async function getAllStudentsHandler(req: Request, res: Response): Promise<void> {
     const full = req.query.full === 'true';
diff --git a/backend/src/controllers/teachers.ts b/backend/src/controllers/teachers.ts
index abb5be69..9275ca92 100644
--- a/backend/src/controllers/teachers.ts
+++ b/backend/src/controllers/teachers.ts
@@ -11,10 +11,7 @@ import {
     updateClassJoinRequestStatus,
 } from '../services/teachers.js';
 import { requireFields } from './error-helper.js';
-import { TeacherDTO } from 'dwengo-1-common/src/interfaces/teacher';
-import { ClassDTO } from 'dwengo-1-common/src/interfaces/class';
-import { StudentDTO } from 'dwengo-1-common/src/interfaces/student';
-import { QuestionDTO, QuestionId } from 'dwengo-1-common/src/interfaces/question';
+import { TeacherDTO } from '@dwengo-1/common/interfaces/teacher';
 
 export async function getAllTeachersHandler(req: Request, res: Response): Promise<void> {
     const full = req.query.full === 'true';
@@ -58,7 +55,7 @@ export async function getTeacherClassHandler(req: Request, res: Response): Promi
     const full = req.query.full === 'true';
     requireFields({ username });
 
-    const classes: ClassDTO[] | string[] = await getClassesByTeacher(username, full);
+    const classes = await getClassesByTeacher(username, full);
 
     res.json({ classes });
 }
@@ -68,7 +65,7 @@ export async function getTeacherStudentHandler(req: Request, res: Response): Pro
     const full = req.query.full === 'true';
     requireFields({ username });
 
-    const students: StudentDTO[] | string[] = await getStudentsByTeacher(username, full);
+    const students = await getStudentsByTeacher(username, full);
 
     res.json({ students });
 }
@@ -78,7 +75,7 @@ export async function getTeacherQuestionHandler(req: Request, res: Response): Pr
     const full = req.query.full === 'true';
     requireFields({ username });
 
-    const questions: QuestionDTO[] | QuestionId[] = await getTeacherQuestions(username, full);
+    const questions = await getTeacherQuestions(username, full);
 
     res.json({ questions });
 }
diff --git a/backend/src/data/themes.ts b/backend/src/data/themes.ts
index fb3ee47c..7bae807a 100644
--- a/backend/src/data/themes.ts
+++ b/backend/src/data/themes.ts
@@ -1,4 +1,4 @@
-import { Theme } from 'dwengo-1-common/src/interfaces/theme';
+import { Theme } from 'common/src/interfaces/theme';
 
 export const themes: Theme[] = [
     {
diff --git a/backend/src/interfaces/question.ts b/backend/src/interfaces/question.ts
index 06ec7878..48d64f11 100644
--- a/backend/src/interfaces/question.ts
+++ b/backend/src/interfaces/question.ts
@@ -1,6 +1,7 @@
 import { Question } from '../entities/questions/question.entity.js';
 import { mapToStudentDTO } from './student.js';
 import { QuestionDTO, QuestionId } from '@dwengo-1/common/interfaces/question';
+import { LearningObjectIdentifier } from '@dwengo-1/common/interfaces/learning-content';
 
 function getLearningObjectIdentifier(question: Question): LearningObjectIdentifier {
     return {
diff --git a/backend/src/interfaces/student-request.ts b/backend/src/interfaces/student-request.ts
index ad45f8fe..31fce14f 100644
--- a/backend/src/interfaces/student-request.ts
+++ b/backend/src/interfaces/student-request.ts
@@ -3,7 +3,7 @@ import { ClassJoinRequest, ClassJoinRequestStatus } from '../entities/classes/cl
 import { getClassJoinRequestRepository } from '../data/repositories.js';
 import { Student } from '../entities/users/student.entity.js';
 import { Class } from '../entities/classes/class.entity.js';
-import { ClassJoinRequestDTO } from 'dwengo-1-common/src/interfaces/class-join-request';
+import { ClassJoinRequestDTO } from 'common/src/interfaces/class-join-request';
 
 export function mapToStudentRequestDTO(request: ClassJoinRequest): ClassJoinRequestDTO {
     return {
diff --git a/backend/src/services/students.ts b/backend/src/services/students.ts
index 3f528dbc..7484277c 100644
--- a/backend/src/services/students.ts
+++ b/backend/src/services/students.ts
@@ -6,17 +6,23 @@ import {
     getStudentRepository,
     getSubmissionRepository,
 } from '../data/repositories.js';
-import { AssignmentDTO } from '../interfaces/assignment.js';
-import { ClassDTO, mapToClassDTO } from '../interfaces/class.js';
-import { GroupDTO, mapToGroupDTO, mapToGroupDTOId } from '../interfaces/group.js';
-import { mapToStudent, mapToStudentDTO, StudentDTO } from '../interfaces/student.js';
-import { mapToSubmissionDTO, mapToSubmissionDTOId, SubmissionDTO, SubmissionDTOId } from '../interfaces/submission.js';
+import { mapToClassDTO } from '../interfaces/class.js';
+import { mapToGroupDTO, mapToGroupDTOId } from '../interfaces/group.js';
+import { mapToStudent, mapToStudentDTO } from '../interfaces/student.js';
+import { mapToSubmissionDTO, mapToSubmissionDTOId } from '../interfaces/submission.js';
 import { getAllAssignments } from './assignments.js';
-import { mapToQuestionDTO, mapToQuestionDTOId, QuestionDTO, QuestionId } from '../interfaces/question.js';
-import { mapToStudentRequest, mapToStudentRequestDTO, StudentRequestDTO } from '../interfaces/student-request.js';
+import { mapToQuestionDTO, mapToQuestionDTOId } from '../interfaces/question.js';
+import { mapToStudentRequest, mapToStudentRequestDTO } from '../interfaces/student-request.js';
 import { Student } from '../entities/users/student.entity.js';
 import { NotFoundException } from '../exceptions/not-found-exception.js';
 import { fetchClass } from './classes.js';
+import { StudentDTO } from '@dwengo-1/common/interfaces/student';
+import { ClassDTO } from '@dwengo-1/common/interfaces/class';
+import { AssignmentDTO } from '@dwengo-1/common/interfaces/assignment';
+import { GroupDTO } from '@dwengo-1/common/interfaces/group';
+import { SubmissionDTO, SubmissionDTOId } from '@dwengo-1/common/interfaces/submission';
+import { QuestionDTO, QuestionId } from '@dwengo-1/common/interfaces/question';
+import {ClassJoinRequestDTO} from '@dwengo-1/common/interfaces/class-join-request';
 
 export async function getAllStudents(full: boolean): Promise<StudentDTO[] | string[]> {
     const studentRepository = getStudentRepository();
@@ -123,7 +129,7 @@ export async function getStudentQuestions(username: string, full: boolean): Prom
     return questions.map(mapToQuestionDTOId);
 }
 
-export async function createClassJoinRequest(username: string, classId: string): Promise<StudentRequestDTO> {
+export async function createClassJoinRequest(username: string, classId: string): Promise<ClassJoinRequestDTO> {
     const requestRepo = getClassJoinRequestRepository();
 
     const student = await fetchStudent(username); // Throws error if student not found
@@ -134,7 +140,7 @@ export async function createClassJoinRequest(username: string, classId: string):
     return mapToStudentRequestDTO(request);
 }
 
-export async function getJoinRequestsByStudent(username: string): Promise<StudentRequestDTO[]> {
+export async function getJoinRequestsByStudent(username: string): Promise<ClassJoinRequestDTO[]> {
     const requestRepo = getClassJoinRequestRepository();
 
     const student = await fetchStudent(username);
@@ -143,7 +149,7 @@ export async function getJoinRequestsByStudent(username: string): Promise<Studen
     return requests.map(mapToStudentRequestDTO);
 }
 
-export async function getJoinRequestByStudentClass(username: string, classId: string): Promise<StudentRequestDTO> {
+export async function getJoinRequestByStudentClass(username: string, classId: string): Promise<ClassJoinRequestDTO> {
     const requestRepo = getClassJoinRequestRepository();
 
     const student = await fetchStudent(username);
@@ -157,7 +163,7 @@ export async function getJoinRequestByStudentClass(username: string, classId: st
     return mapToStudentRequestDTO(request);
 }
 
-export async function deleteClassJoinRequest(username: string, classId: string): Promise<StudentRequestDTO> {
+export async function deleteClassJoinRequest(username: string, classId: string): Promise<ClassJoinRequestDTO> {
     const requestRepo = getClassJoinRequestRepository();
 
     const student = await fetchStudent(username);
diff --git a/backend/src/services/teachers.ts b/backend/src/services/teachers.ts
index 98ac0a83..1b7643fb 100644
--- a/backend/src/services/teachers.ts
+++ b/backend/src/services/teachers.ts
@@ -5,17 +5,16 @@ import {
     getQuestionRepository,
     getTeacherRepository,
 } from '../data/repositories.js';
-import { ClassDTO, mapToClassDTO } from '../interfaces/class.js';
-import { mapToQuestionDTO, mapToQuestionDTOId, QuestionDTO, QuestionId } from '../interfaces/question.js';
-import { mapToTeacher, mapToTeacherDTO, TeacherDTO } from '../interfaces/teacher.js';
+import { mapToClassDTO } from '../interfaces/class.js';
+import { mapToQuestionDTO, mapToQuestionDTOId } from '../interfaces/question.js';
+import { mapToTeacher, mapToTeacherDTO } from '../interfaces/teacher.js';
 import { Teacher } from '../entities/users/teacher.entity.js';
 import { fetchStudent } from './students.js';
-import { ClassJoinRequest, ClassJoinRequestStatus } from '../entities/classes/class-join-request.entity.js';
-import { mapToStudentRequestDTO, StudentRequestDTO } from '../interfaces/student-request.js';
+import { ClassJoinRequest } from '../entities/classes/class-join-request.entity.js';
+import { mapToStudentRequestDTO } from '../interfaces/student-request.js';
 import { TeacherRepository } from '../data/users/teacher-repository.js';
 import { ClassRepository } from '../data/classes/class-repository.js';
 import { Class } from '../entities/classes/class.entity.js';
-import { StudentDTO } from '../interfaces/student.js';
 import { LearningObjectRepository } from '../data/content/learning-object-repository.js';
 import { LearningObject } from '../entities/content/learning-object.entity.js';
 import { QuestionRepository } from '../data/questions/question-repository.js';
@@ -24,6 +23,12 @@ import { ClassJoinRequestRepository } from '../data/classes/class-join-request-r
 import { Student } from '../entities/users/student.entity.js';
 import { NotFoundException } from '../exceptions/not-found-exception.js';
 import { getClassStudents } from './classes.js';
+import { TeacherDTO } from '@dwengo-1/common/interfaces/teacher';
+import { ClassDTO } from '@dwengo-1/common/interfaces/class';
+import { StudentDTO } from '@dwengo-1/common/interfaces/student';
+import { QuestionDTO, QuestionId } from '@dwengo-1/common/interfaces/question';
+import { ClassJoinRequestDTO } from '@dwengo-1/common/interfaces/class-join-request';
+import { ClassJoinRequestStatus } from '@dwengo-1/common/util/class-join-request';
 
 export async function getAllTeachers(full: boolean): Promise<TeacherDTO[] | string[]> {
     const teacherRepository: TeacherRepository = getTeacherRepository();
@@ -123,7 +128,7 @@ export async function getTeacherQuestions(username: string, full: boolean): Prom
     return questions.map(mapToQuestionDTOId);
 }
 
-export async function getJoinRequestsByClass(classId: string): Promise<StudentRequestDTO[]> {
+export async function getJoinRequestsByClass(classId: string): Promise<ClassJoinRequestDTO[]> {
     const classRepository: ClassRepository = getClassRepository();
     const cls: Class | null = await classRepository.findById(classId);
 
@@ -136,7 +141,7 @@ export async function getJoinRequestsByClass(classId: string): Promise<StudentRe
     return requests.map(mapToStudentRequestDTO);
 }
 
-export async function updateClassJoinRequestStatus(studentUsername: string, classId: string, accepted = true): Promise<StudentRequestDTO> {
+export async function updateClassJoinRequestStatus(studentUsername: string, classId: string, accepted = true): Promise<ClassJoinRequestDTO> {
     const requestRepo: ClassJoinRequestRepository = getClassJoinRequestRepository();
     const classRepo: ClassRepository = getClassRepository();
 
diff --git a/backend/tests/controllers/students.test.ts b/backend/tests/controllers/students.test.ts
index 44919c4a..05151d03 100644
--- a/backend/tests/controllers/students.test.ts
+++ b/backend/tests/controllers/students.test.ts
@@ -20,7 +20,8 @@ import { NotFoundException } from '../../src/exceptions/not-found-exception.js';
 import { BadRequestException } from '../../src/exceptions/bad-request-exception.js';
 import { ConflictException } from '../../src/exceptions/conflict-exception.js';
 import { EntityAlreadyExistsException } from '../../src/exceptions/entity-already-exists-exception.js';
-import { StudentDTO } from 'dwengo-1-common/src/interfaces/student';
+import { StudentDTO } from '@dwengo-1/common/interfaces/student';
+
 
 describe('Student controllers', () => {
     let req: Partial<Request>;
diff --git a/backend/tests/controllers/teachers.test.ts b/backend/tests/controllers/teachers.test.ts
index e5b33ea8..bee23987 100644
--- a/backend/tests/controllers/teachers.test.ts
+++ b/backend/tests/controllers/teachers.test.ts
@@ -15,7 +15,7 @@ import {
 import { BadRequestException } from '../../src/exceptions/bad-request-exception.js';
 import { EntityAlreadyExistsException } from '../../src/exceptions/entity-already-exists-exception.js';
 import { getStudentRequestsHandler } from '../../src/controllers/students.js';
-import { TeacherDTO } from 'dwengo-1-common/src/interfaces/teacher';
+import { TeacherDTO } from '@dwengo-1/common/interfaces/teacher';
 
 describe('Teacher controllers', () => {
     let req: Partial<Request>;
diff --git a/common/src/interfaces/class-join-request.d.ts b/common/src/interfaces/class-join-request.ts
similarity index 70%
rename from common/src/interfaces/class-join-request.d.ts
rename to common/src/interfaces/class-join-request.ts
index 4ba6d520..0af70272 100644
--- a/common/src/interfaces/class-join-request.d.ts
+++ b/common/src/interfaces/class-join-request.ts
@@ -1,4 +1,5 @@
 import { StudentDTO } from './student';
+import {ClassJoinRequestStatus} from "../util/class-join-request";
 
 export interface ClassJoinRequestDTO {
     requester: StudentDTO;
diff --git a/common/src/interfaces/theme.d.ts b/common/src/interfaces/theme.ts
similarity index 100%
rename from common/src/interfaces/theme.d.ts
rename to common/src/interfaces/theme.ts
diff --git a/frontend/src/controllers/assignments.ts b/frontend/src/controllers/assignments.ts
index f6da213e..5fd5090a 100644
--- a/frontend/src/controllers/assignments.ts
+++ b/frontend/src/controllers/assignments.ts
@@ -1,4 +1,4 @@
-import type { AssignmentDTO } from "dwengo-1-common/src/interfaces/assignment";
+import type { AssignmentDTO } from "@dwengo-1/interfaces/assignment";
 
 export interface AssignmentsResponse {
     assignments: AssignmentDTO[];
diff --git a/frontend/src/controllers/classes.ts b/frontend/src/controllers/classes.ts
index c0755cac..d2d95ed5 100644
--- a/frontend/src/controllers/classes.ts
+++ b/frontend/src/controllers/classes.ts
@@ -1,4 +1,4 @@
-import type { ClassDTO } from "dwengo-1-common/src/interfaces/class";
+import type { ClassDTO } from "@dwengo-1/interfaces/class";
 
 export interface ClassesResponse {
     classes: ClassDTO[] | string[];
diff --git a/frontend/src/controllers/groups.ts b/frontend/src/controllers/groups.ts
index 4cc83dea..d6738e04 100644
--- a/frontend/src/controllers/groups.ts
+++ b/frontend/src/controllers/groups.ts
@@ -1,4 +1,4 @@
-import type { GroupDTO } from "dwengo-1-common/src/interfaces/group";
+import type { GroupDTO } from "@dwengo-1/interfaces/group";
 
 export interface GroupsResponse {
     groups: GroupDTO[];
diff --git a/frontend/src/controllers/questions.ts b/frontend/src/controllers/questions.ts
index 0464578c..9b0182de 100644
--- a/frontend/src/controllers/questions.ts
+++ b/frontend/src/controllers/questions.ts
@@ -1,4 +1,4 @@
-import type { QuestionDTO, QuestionId } from "dwengo-1-common/src/interfaces/question";
+import type { QuestionDTO, QuestionId } from "@dwengo-1/interfaces/question";
 
 export interface QuestionsResponse {
     questions: QuestionDTO[] | QuestionId[];
diff --git a/frontend/src/controllers/students.ts b/frontend/src/controllers/students.ts
index 0640a971..b36f1d5a 100644
--- a/frontend/src/controllers/students.ts
+++ b/frontend/src/controllers/students.ts
@@ -1,11 +1,11 @@
 import { BaseController } from "@/controllers/base-controller.ts";
-import type { StudentDTO } from "dwengo-1-common/src/interfaces/student";
 import type { ClassesResponse } from "@/controllers/classes.ts";
 import type { AssignmentsResponse } from "@/controllers/assignments.ts";
 import type { GroupsResponse } from "@/controllers/groups.ts";
 import type { SubmissionsResponse } from "@/controllers/submissions.ts";
 import type { QuestionsResponse } from "@/controllers/questions.ts";
-import type { ClassJoinRequestDTO } from "dwengo-1-common/src/interfaces/class-join-request";
+import type { StudentDTO } from "@dwengo-1/interfaces/student";
+import type { ClassJoinRequestDTO } from "@dwengo-1/interfaces/class-join-request";
 
 export interface StudentsResponse {
     students: StudentDTO[] | string[];
diff --git a/frontend/src/controllers/submissions.ts b/frontend/src/controllers/submissions.ts
index fa16cbaf..99b6ba8d 100644
--- a/frontend/src/controllers/submissions.ts
+++ b/frontend/src/controllers/submissions.ts
@@ -1,4 +1,4 @@
-import { type SubmissionDTO, SubmissionDTOId } from "dwengo-1-common/src/interfaces/submission";
+import { type SubmissionDTO, SubmissionDTOId } from "@dwengo-1/interfaces/submission";
 
 export interface SubmissionsResponse {
     submissions: SubmissionDTO[] | SubmissionDTOId[];
diff --git a/frontend/src/controllers/teachers.ts b/frontend/src/controllers/teachers.ts
index d356e3a2..e0d38a6c 100644
--- a/frontend/src/controllers/teachers.ts
+++ b/frontend/src/controllers/teachers.ts
@@ -2,7 +2,7 @@ import { BaseController } from "@/controllers/base-controller.ts";
 import type { JoinRequestResponse, JoinRequestsResponse, StudentsResponse } from "@/controllers/students.ts";
 import type { QuestionsResponse } from "@/controllers/questions.ts";
 import type { ClassesResponse } from "@/controllers/classes.ts";
-import type { TeacherDTO } from "dwengo-1-common/src/interfaces/teacher";
+import type { TeacherDTO } from "@dwengo-1/interfaces/teacher";
 
 export interface TeachersResponse {
     teachers: TeacherDTO[] | string[];
diff --git a/frontend/src/controllers/themes.ts b/frontend/src/controllers/themes.ts
index c810bf93..bb76249d 100644
--- a/frontend/src/controllers/themes.ts
+++ b/frontend/src/controllers/themes.ts
@@ -1,5 +1,5 @@
 import { BaseController } from "@/controllers/base-controller.ts";
-import type { Theme } from "dwengo-1-common/src/interfaces/theme";
+import type { Theme } from "@dwengo-1/interfaces/theme";
 
 export class ThemeController extends BaseController {
     constructor() {
diff --git a/frontend/src/queries/themes.ts b/frontend/src/queries/themes.ts
index 75a6d876..c474efcd 100644
--- a/frontend/src/queries/themes.ts
+++ b/frontend/src/queries/themes.ts
@@ -1,7 +1,7 @@
 import { useQuery, type UseQueryReturnType } from "@tanstack/vue-query";
 import { type MaybeRefOrGetter, toValue } from "vue";
 import { ThemeController } from "@/controllers/themes.ts";
-import type { Theme } from "dwengo-1-common/src/interfaces/theme";
+import type { Theme } from "../../../common/src/interfaces/theme";
 
 const themeController = new ThemeController();