diff --git a/backend/src/controllers/questions.ts b/backend/src/controllers/questions.ts
index 00a51329..0f0604b2 100644
--- a/backend/src/controllers/questions.ts
+++ b/backend/src/controllers/questions.ts
@@ -1,9 +1,9 @@
 import { Request, Response } from 'express';
 import { createQuestion, deleteQuestion, getAllQuestions, getAnswersByQuestion, getQuestion } from '../services/questions.js';
-import { QuestionDTO, QuestionId } from '../interfaces/question.js';
 import { FALLBACK_LANG, FALLBACK_SEQ_NUM } from '../config.js';
 import { LearningObjectIdentifier } from '../entities/content/learning-object-identifier.js';
 import { Language } from '../entities/content/language.js';
+import { QuestionDTO, QuestionId } from 'dwengo-1-common/src/interfaces/question';
 
 function getObjectId(req: Request, res: Response): LearningObjectIdentifier | null {
     const { hruid, version } = req.params;
diff --git a/backend/src/interfaces/question.ts b/backend/src/interfaces/question.ts
index 93019dae..86cd6523 100644
--- a/backend/src/interfaces/question.ts
+++ b/backend/src/interfaces/question.ts
@@ -1,15 +1,6 @@
 import { Question } from '../entities/questions/question.entity.js';
-import { LearningObjectIdentifier } from '../entities/content/learning-object-identifier.js';
 import { mapToStudentDTO } from './student.js';
-import { StudentDTO } from 'dwengo-1-common/src/interfaces/student';
-
-export interface QuestionDTO {
-    learningObjectIdentifier: LearningObjectIdentifier;
-    sequenceNumber?: number;
-    author: StudentDTO;
-    timestamp?: string;
-    content: string;
-}
+import { QuestionDTO, QuestionId } from 'dwengo-1-common/src/interfaces/question';
 
 /**
  * Convert a Question entity to a DTO format.
@@ -30,11 +21,6 @@ export function mapToQuestionDTO(question: Question): QuestionDTO {
     };
 }
 
-export interface QuestionId {
-    learningObjectIdentifier: LearningObjectIdentifier;
-    sequenceNumber: number;
-}
-
 export function mapToQuestionId(question: QuestionDTO): QuestionId {
     return {
         learningObjectIdentifier: question.learningObjectIdentifier,
diff --git a/backend/src/services/questions.ts b/backend/src/services/questions.ts
index 0e52440f..ed61902e 100644
--- a/backend/src/services/questions.ts
+++ b/backend/src/services/questions.ts
@@ -1,5 +1,5 @@
 import { getAnswerRepository, getQuestionRepository } from '../data/repositories.js';
-import { mapToQuestionDTO, mapToQuestionId, QuestionDTO, QuestionId } from '../interfaces/question.js';
+import { mapToQuestionDTO, mapToQuestionId } from '../interfaces/question.js';
 import { Question } from '../entities/questions/question.entity.js';
 import { Answer } from '../entities/questions/answer.entity.js';
 import { mapToAnswerDTO, mapToAnswerId } from '../interfaces/answer.js';
@@ -8,6 +8,7 @@ import { LearningObjectIdentifier } from '../entities/content/learning-object-id
 import { mapToUser } from '../interfaces/user.js';
 import { Student } from '../entities/users/student.entity.js';
 import { mapToStudent } from '../interfaces/student.js';
+import { QuestionDTO, QuestionId } from 'dwengo-1-common/src/interfaces/question';
 
 export async function getAllQuestions(id: LearningObjectIdentifier, full: boolean): Promise<QuestionDTO[] | QuestionId[]> {
     const questionRepository: QuestionRepository = getQuestionRepository();
diff --git a/backend/src/services/teachers.ts b/backend/src/services/teachers.ts
index 3b2a5bbb..aa6ce2d8 100644
--- a/backend/src/services/teachers.ts
+++ b/backend/src/services/teachers.ts
@@ -1,11 +1,12 @@
 import { getClassRepository, getLearningObjectRepository, getQuestionRepository, getTeacherRepository } from '../data/repositories.js';
 import { mapToClassDTO } from '../interfaces/class.js';
 import { getClassStudents } from './classes.js';
-import { mapToQuestionDTO, mapToQuestionId, QuestionDTO, QuestionId } from '../interfaces/question.js';
+import { mapToQuestionDTO, mapToQuestionId } from '../interfaces/question.js';
 import { mapToTeacher, mapToTeacherDTO } from '../interfaces/teacher.js';
 import { ClassDTO } from 'dwengo-1-common/src/interfaces/class';
 import { TeacherDTO } from 'dwengo-1-common/src/interfaces/teacher';
 import { StudentDTO } from 'dwengo-1-common/src/interfaces/student';
+import { QuestionDTO, QuestionId } from 'dwengo-1-common/src/interfaces/question';
 
 export async function getAllTeachers(full: boolean): Promise<TeacherDTO[] | string[]> {
     const teacherRepository = getTeacherRepository();
diff --git a/common/src/interfaces/answer.d.ts b/common/src/interfaces/answer.d.ts
index b8fc9b55..d2faf87d 100644
--- a/common/src/interfaces/answer.d.ts
+++ b/common/src/interfaces/answer.d.ts
@@ -1,5 +1,5 @@
-import { QuestionDTO } from 'dwengo-1-backend/src/interfaces/question.js';
 import { UserDTO } from './user';
+import { QuestionDTO } from './question';
 
 export interface AnswerDTO {
     author: UserDTO;
diff --git a/common/src/interfaces/question.d.ts b/common/src/interfaces/question.d.ts
new file mode 100644
index 00000000..2b2a263c
--- /dev/null
+++ b/common/src/interfaces/question.d.ts
@@ -0,0 +1,14 @@
+import { StudentDTO } from './student';
+
+export interface QuestionDTO {
+    learningObjectIdentifier: LearningObjectIdentifier;
+    sequenceNumber?: number;
+    author: StudentDTO;
+    timestamp?: string;
+    content: string;
+}
+
+export interface QuestionId {
+    learningObjectIdentifier: LearningObjectIdentifier;
+    sequenceNumber: number;
+}