diff --git a/backend/src/controllers/teachers.ts b/backend/src/controllers/teachers.ts
index 7376abed..7f1beb54 100644
--- a/backend/src/controllers/teachers.ts
+++ b/backend/src/controllers/teachers.ts
@@ -8,7 +8,8 @@ import {
     getStudentsByTeacher,
     getTeacher,
 } from '../services/teachers.js';
-import { TeacherDTO } from '../interfaces/teacher.js';
+
+import { TeacherDTO } from 'dwengo-1-common/src/interfaces/teacher';
 
 export async function getAllTeachersHandler(req: Request, res: Response): Promise<void> {
     const full = req.query.full === 'true';
diff --git a/backend/src/interfaces/teacher-invitation.ts b/backend/src/interfaces/teacher-invitation.ts
index 8a792280..8df92fd1 100644
--- a/backend/src/interfaces/teacher-invitation.ts
+++ b/backend/src/interfaces/teacher-invitation.ts
@@ -1,14 +1,7 @@
 import { TeacherInvitation } from '../entities/classes/teacher-invitation.entity.js';
 import { mapToClassDTO } from './class.js';
 import { mapToUserDTO } from './user.js';
-import { ClassDTO } from 'dwengo-1-common/src/interfaces/class';
-import { UserDTO } from 'dwengo-1-common/src/interfaces/user';
-
-export interface TeacherInvitationDTO {
-    sender: string | UserDTO;
-    receiver: string | UserDTO;
-    class: string | ClassDTO;
-}
+import { TeacherInvitationDTO } from 'dwengo-1-common/src/interfaces/teacher-invitation';
 
 export function mapToTeacherInvitationDTO(invitation: TeacherInvitation): TeacherInvitationDTO {
     return {
diff --git a/backend/src/interfaces/teacher.ts b/backend/src/interfaces/teacher.ts
index 31b4723f..a1ba33fd 100644
--- a/backend/src/interfaces/teacher.ts
+++ b/backend/src/interfaces/teacher.ts
@@ -1,18 +1,6 @@
 import { Teacher } from '../entities/users/teacher.entity.js';
 import { getTeacherRepository } from '../data/repositories.js';
-
-export interface TeacherDTO {
-    id: string;
-    username: string;
-    firstName: string;
-    lastName: string;
-    endpoints?: {
-        classes: string;
-        questions: string;
-        invitations: string;
-        groups: string;
-    };
-}
+import { TeacherDTO } from 'dwengo-1-common/src/interfaces/teacher';
 
 export function mapToTeacherDTO(teacher: Teacher): TeacherDTO {
     return {
diff --git a/backend/src/services/classes.ts b/backend/src/services/classes.ts
index 542f8f19..ecc4b43e 100644
--- a/backend/src/services/classes.ts
+++ b/backend/src/services/classes.ts
@@ -1,9 +1,10 @@
 import { getClassRepository, getStudentRepository, getTeacherInvitationRepository, getTeacherRepository } from '../data/repositories.js';
 import { mapToClassDTO } from '../interfaces/class.js';
 import { mapToStudentDTO, StudentDTO } from '../interfaces/student.js';
-import { mapToTeacherInvitationDTO, mapToTeacherInvitationDTOIds, TeacherInvitationDTO } from '../interfaces/teacher-invitation.js';
+import { mapToTeacherInvitationDTO, mapToTeacherInvitationDTOIds } from '../interfaces/teacher-invitation.js';
 import { getLogger } from '../logging/initalize.js';
 import { ClassDTO } from 'dwengo-1-common/src/interfaces/class';
+import { TeacherInvitationDTO } from 'dwengo-1-common/src/interfaces/teacher-invitation';
 
 const logger = getLogger();
 
diff --git a/backend/src/services/teachers.ts b/backend/src/services/teachers.ts
index eca54214..9589d0ba 100644
--- a/backend/src/services/teachers.ts
+++ b/backend/src/services/teachers.ts
@@ -3,8 +3,9 @@ import { mapToClassDTO } from '../interfaces/class.js';
 import { getClassStudents } from './classes.js';
 import { StudentDTO } from '../interfaces/student.js';
 import { mapToQuestionDTO, mapToQuestionId, QuestionDTO, QuestionId } from '../interfaces/question.js';
-import { mapToTeacher, mapToTeacherDTO, TeacherDTO } from '../interfaces/teacher.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';
 
 export async function getAllTeachers(full: boolean): Promise<TeacherDTO[] | string[]> {
     const teacherRepository = getTeacherRepository();
diff --git a/common/src/interfaces/teacher-invitation.d.ts b/common/src/interfaces/teacher-invitation.d.ts
new file mode 100644
index 00000000..13709322
--- /dev/null
+++ b/common/src/interfaces/teacher-invitation.d.ts
@@ -0,0 +1,8 @@
+import { UserDTO } from './user';
+import { ClassDTO } from './class';
+
+export interface TeacherInvitationDTO {
+    sender: string | UserDTO;
+    receiver: string | UserDTO;
+    class: string | ClassDTO;
+}
diff --git a/common/src/interfaces/teacher.d.ts b/common/src/interfaces/teacher.d.ts
new file mode 100644
index 00000000..05bf74a0
--- /dev/null
+++ b/common/src/interfaces/teacher.d.ts
@@ -0,0 +1,12 @@
+export interface TeacherDTO {
+    id: string;
+    username: string;
+    firstName: string;
+    lastName: string;
+    endpoints?: {
+        classes: string;
+        questions: string;
+        invitations: string;
+        groups: string;
+    };
+}