diff --git a/frontend/src/controllers/assignments.ts b/frontend/src/controllers/assignments.ts
index e255ad66..59ea2428 100644
--- a/frontend/src/controllers/assignments.ts
+++ b/frontend/src/controllers/assignments.ts
@@ -17,31 +17,31 @@ export class AssignmentController extends BaseController {
         super(`class/${classid}/assignments`);
     }
 
-    async getAll(full = true) {
+    async getAll(full = true): Promise<AssignmentsResponse> {
         return this.get<AssignmentsResponse>(`/`, { full });
     }
 
-    async getByNumber(num: number) {
+    async getByNumber(num: number): Promise<AssignmentResponse> {
         return this.get<AssignmentResponse>(`/${num}`);
     }
 
-    async createAssignment(data: any) {
+    async createAssignment(data: AssignmentDTO): Promise<AssignmentResponse> {
         return this.post<AssignmentResponse>(`/`, data);
     }
 
-    async deleteAssignment(num: number) {
+    async deleteAssignment(num: number): Promise<AssignmentResponse> {
         return this.delete<AssignmentResponse>(`/${num}`);
     }
 
-    async getSubmissions(assignmentNumber: number, full = true) {
+    async getSubmissions(assignmentNumber: number, full = true): Promise<SubmissionsResponse> {
         return this.get<SubmissionsResponse>(`/${assignmentNumber}/submissions`, { full });
     }
 
-    async getQuestions(assignmentNumber: number, full = true) {
+    async getQuestions(assignmentNumber: number, full = true): Promise<QuestionsResponse> {
         return this.get<QuestionsResponse>(`/${assignmentNumber}/questions`, { full });
     }
 
-    async getGroups(assignmentNumber: number, full = true) {
+    async getGroups(assignmentNumber: number, full = true): Promise<GroupsResponse> {
         return this.get<GroupsResponse>(`/${assignmentNumber}/groups`, { full });
     }
 }
diff --git a/frontend/src/controllers/classes.ts b/frontend/src/controllers/classes.ts
index 374f0f6e..dadf6dec 100644
--- a/frontend/src/controllers/classes.ts
+++ b/frontend/src/controllers/classes.ts
@@ -2,6 +2,7 @@ import { BaseController } from "./base-controller";
 import type { ClassDTO } from "@dwengo-1/common/interfaces/class";
 import type { StudentsResponse } from "./students";
 import type { AssignmentsResponse } from "./assignments";
+import type { TeacherInvitationDTO } from "@dwengo-1/common/interfaces/teacher-invitation";
 
 export interface ClassesResponse {
     classes: ClassDTO[] | string[];
@@ -11,37 +12,45 @@ export interface ClassResponse {
     class: ClassDTO;
 }
 
+export interface TeacherInvitationsResponse {
+    invites: TeacherInvitationDTO[];
+}
+
+export interface TeacherInvitationResponse {
+    invite: TeacherInvitationDTO;
+}
+
 export class ClassController extends BaseController {
     constructor() {
         super("class");
     }
 
-    async getAll(full = true) {
+    async getAll(full = true): Promise<ClassesResponse> {
         return this.get<ClassesResponse>(`/`, { full });
     }
 
-    async getById(id: string) {
+    async getById(id: string): Promise<ClassResponse> {
         return this.get<ClassResponse>(`/${id}`);
     }
 
-    async createClass(data: any) {
+    async createClass(data: ClassDTO): Promise<ClassResponse> {
         return this.post<ClassResponse>(`/`, data);
     }
 
-    async deleteClass(id: string) {
+    async deleteClass(id: string): Promise<ClassResponse> {
         return this.delete<ClassResponse>(`/${id}`);
     }
 
-    async getStudents(id: string, full = true) {
+    async getStudents(id: string, full = true): Promise<StudentsResponse> {
         return this.get<StudentsResponse>(`/${id}/students`, { full });
     }
 
     // TODO
-    async getTeacherInvitations(id: string, full = true) {
-        return this.get<any>(`/${id}/teacher-invitations`, { full });
+    async getTeacherInvitations(id: string, full = true): Promise<TeacherInvitationsResponse> {
+        return this.get<TeacherInvitationsResponse>(`/${id}/teacher-invitations`, { full });
     }
 
-    async getAssignments(id: string, full = true) {
+    async getAssignments(id: string, full = true): Promise<AssignmentsResponse> {
         return this.get<AssignmentsResponse>(`/${id}/assignments`, { full });
     }
 }
diff --git a/frontend/src/controllers/groups.ts b/frontend/src/controllers/groups.ts
index e82e5607..05192636 100644
--- a/frontend/src/controllers/groups.ts
+++ b/frontend/src/controllers/groups.ts
@@ -16,27 +16,27 @@ export class GroupController extends BaseController {
         super(`class/${classid}/assignments/${assignmentNumber}/groups`);
     }
 
-    async getAll(full = true) {
+    async getAll(full = true): Promise<GroupsResponse> {
         return this.get<GroupsResponse>(`/`, { full });
     }
 
-    async getByNumber(num: number) {
+    async getByNumber(num: number): Promise<GroupResponse> {
         return this.get<GroupResponse>(`/${num}`);
     }
 
-    async createGroup(data: any) {
+    async createGroup(data: GroupDTO): Promise<GroupResponse> {
         return this.post<GroupResponse>(`/`, data);
     }
 
-    async deleteGroup(num: number) {
+    async deleteGroup(num: number): Promise<GroupResponse> {
         return this.delete<GroupResponse>(`/${num}`);
     }
 
-    async getSubmissions(groupNumber: number, full = true) {
+    async getSubmissions(groupNumber: number, full = true): Promise<SubmissionsResponse> {
         return this.get<SubmissionsResponse>(`/${groupNumber}/submissions`, { full });
     }
 
-    async getQuestions(groupNumber: number, full = true) {
+    async getQuestions(groupNumber: number, full = true): Promise<QuestionsResponse> {
         return this.get<QuestionsResponse>(`/${groupNumber}/questions`, { full });
     }
 }
diff --git a/frontend/src/controllers/submissions.ts b/frontend/src/controllers/submissions.ts
index 72621fcf..07e8e16c 100644
--- a/frontend/src/controllers/submissions.ts
+++ b/frontend/src/controllers/submissions.ts
@@ -14,19 +14,19 @@ export class SubmissionController extends BaseController {
         super(`class/${classid}/assignments/${assignmentNumber}/groups/${groupNumber}`);
     }
 
-    async getAll(full = true) {
+    async getAll(full = true): Promise<SubmissionsResponse> {
         return this.get<SubmissionsResponse>(`/`, { full });
     }
 
-    async getByNumber(submissionNumber: number) {
+    async getByNumber(submissionNumber: number): Promise<SubmissionResponse> {
         return this.get<SubmissionResponse>(`/${submissionNumber}`);
     }
 
-    async createSubmission(data: any) {
+    async createSubmission(data: any): Promise<SubmissionResponse> {
         return this.post<SubmissionResponse>(`/`, data);
     }
 
-    async deleteSubmission(submissionNumber: number) {
+    async deleteSubmission(submissionNumber: number): Promise<SubmissionResponse> {
         return this.delete<SubmissionResponse>(`/${submissionNumber}`);
     }
 }