diff --git a/src/models/partyplaner/PartyPlaner.router.ts b/src/models/partyplaner/PartyPlaner.router.ts
index ffabc40..951bd46 100644
--- a/src/models/partyplaner/PartyPlaner.router.ts
+++ b/src/models/partyplaner/PartyPlaner.router.ts
@@ -2,10 +2,14 @@
  * Required External Modules and Interfaces
  */
 import express, {Request, Response} from 'express';
-import {dataRouter} from './data/Data.router';
 import {registerRouter} from './register/Register.router';
 import logger from '../../middleware/logger';
 import {loginRouter} from './login/Login.router';
+import {userRouter} from './user/User.router';
+import {eventRouter} from './event/Event.router';
+import {friendshipRouter} from './friendship/Friendship.router';
+import {inviteRouter} from './invite/Invite.router';
+import {sessionRouter} from './session/Session.router';
 
 /**
  * Router Definition
@@ -13,9 +17,13 @@ import {loginRouter} from './login/Login.router';
 export const partyPlanerRouter = express.Router();
 
 // Sub-Endpoints
-partyPlanerRouter.use('/data', dataRouter);
-partyPlanerRouter.use('/register', registerRouter);
+partyPlanerRouter.use('/event', eventRouter);
+partyPlanerRouter.use('/friendship', friendshipRouter);
+partyPlanerRouter.use('/invite', inviteRouter);
 partyPlanerRouter.use('/login', loginRouter);
+partyPlanerRouter.use('/register', registerRouter);
+partyPlanerRouter.use('/session', sessionRouter);
+partyPlanerRouter.use('/user', userRouter);
 
 partyPlanerRouter.get('/', async (req: Request, res: Response) => {
     try {
diff --git a/src/models/partyplaner/data/Data.router.ts b/src/models/partyplaner/data/Data.router.ts
deleted file mode 100644
index 0ec41bf..0000000
--- a/src/models/partyplaner/data/Data.router.ts
+++ /dev/null
@@ -1,172 +0,0 @@
-/**
- * Required External Modules and Interfaces
- */
-import express, {Request, Response} from 'express';
-import * as DataService from './data.service';
-import * as UserService from '../userService/user.service';
-import logger from '../../../middleware/logger';
-
-/**
- * Router Definition
- */
-export const dataRouter = express.Router();
-
-dataRouter.get('/user/:isDevCall', async (req: Request, res: Response) => {
-    try {
-        let userId = (req.query.userId ?? '').toString();
-        let sessionId = (req.query.sessionId ?? '').toString();
-        let sessionKey = (req.query.sessionKey ?? '').toString();
-        let useDev: boolean = (req.params.isDevCall ?? '') === 'dev'; // TBD
-
-        if (userId === '' || sessionId === '' || sessionKey === '') {
-            res.status(400).send({
-                'status': 'WRONG_PARAMS',
-                'message': 'Missing or wrong parameters'
-            });
-            return;
-        }
-
-        if (!await UserService.checkSession(useDev, userId, sessionId, sessionKey)) {
-            res.status(403).send({
-                'status': 'INVALID_SESSION',
-                'message': 'The user or session could not be found or the session is invalid'
-            });
-            return;
-        }
-
-        let data = await DataService.getUserData(useDev, userId);
-
-        res.status(200).send(data);
-    } catch (e) {
-        logger.error('Error handling a request: ' + e.message);
-        res.status(500).send({'message': 'Internal Server Error. Try again later.'});
-    }
-});
-
-dataRouter.get('/session/:isDevCall', async (req: Request, res: Response) => {
-    try {
-        let userId = (req.query.userId ?? '').toString();
-        let sessionId = (req.query.sessionId ?? '').toString();
-        let sessionKey = (req.query.sessionKey ?? '').toString();
-        let useDev: boolean = (req.params.isDevCall ?? '') === 'dev'; // TBD
-
-        if (userId === '' || sessionId === '' || sessionKey === '') {
-            res.status(400).send({
-                'status': 'WRONG_PARAMS',
-                'message': 'Missing or wrong parameters'
-            });
-            return;
-        }
-
-        if (!await UserService.checkSession(useDev, userId, sessionId, sessionKey)) {
-            res.status(403).send({
-                'status': 'INVALID_SESSION',
-                'message': 'The user or session could not be found or the session is invalid'
-            });
-            return;
-        }
-
-        let data = await DataService.getSessionData(useDev, userId);
-
-        res.status(200).send(data);
-    } catch (e) {
-        logger.error('Error handling a request: ' + e.message);
-        res.status(500).send({'message': 'Internal Server Error. Try again later.'});
-    }
-});
-
-dataRouter.get('/friendship/:isDevCall', async (req: Request, res: Response) => {
-    try {
-        let userId = (req.query.userId ?? '').toString();
-        let sessionId = (req.query.sessionId ?? '').toString();
-        let sessionKey = (req.query.sessionKey ?? '').toString();
-        let useDev: boolean = (req.params.isDevCall ?? '') === 'dev'; // TBD
-
-        if (userId === '' || sessionId === '' || sessionKey === '') {
-            res.status(400).send({
-                'status': 'WRONG_PARAMS',
-                'message': 'Missing or wrong parameters'
-            });
-            return;
-        }
-
-        if (!await UserService.checkSession(useDev, userId, sessionId, sessionKey)) {
-            res.status(403).send({
-                'status': 'INVALID_SESSION',
-                'message': 'The user or session could not be found or the session is invalid'
-            });
-            return;
-        }
-
-        let data = await DataService.getFriendshipData(useDev, userId);
-
-        res.status(200).send(data);
-    } catch (e) {
-        logger.error('Error handling a request: ' + e.message);
-        res.status(500).send({'message': 'Internal Server Error. Try again later.'});
-    }
-});
-
-dataRouter.get('/event/:isDevCall', async (req: Request, res: Response) => {
-    try {
-        let userId = (req.query.userId ?? '').toString();
-        let sessionId = (req.query.sessionId ?? '').toString();
-        let sessionKey = (req.query.sessionKey ?? '').toString();
-        let useDev: boolean = (req.params.isDevCall ?? '') === 'dev'; // TBD
-
-        if (userId === '' || sessionId === '' || sessionKey === '') {
-            res.status(400).send({
-                'status': 'WRONG_PARAMS',
-                'message': 'Missing or wrong parameters'
-            });
-            return;
-        }
-
-        if (!await UserService.checkSession(useDev, userId, sessionId, sessionKey)) {
-            res.status(403).send({
-                'status': 'INVALID_SESSION',
-                'message': 'The user or session could not be found or the session is invalid'
-            });
-            return;
-        }
-
-        let data = await DataService.getEventData(useDev, userId);
-
-        res.status(200).send(data);
-    } catch (e) {
-        logger.error('Error handling a request: ' + e.message);
-        res.status(500).send({'message': 'Internal Server Error. Try again later.'});
-    }
-});
-
-dataRouter.get('/invite/:isDevCall', async (req: Request, res: Response) => {
-    try {
-        let userId = (req.query.userId ?? '').toString();
-        let sessionId = (req.query.sessionId ?? '').toString();
-        let sessionKey = (req.query.sessionKey ?? '').toString();
-        let useDev: boolean = (req.params.isDevCall ?? '') === 'dev'; // TBD
-
-        if (userId === '' || sessionId === '' || sessionKey === '') {
-            res.status(400).send({
-                'status': 'WRONG_PARAMS',
-                'message': 'Missing or wrong parameters'
-            });
-            return;
-        }
-
-        if (!await UserService.checkSession(useDev, userId, sessionId, sessionKey)) {
-            res.status(403).send({
-                'status': 'INVALID_SESSION',
-                'message': 'The user or session could not be found or the session is invalid'
-            });
-            return;
-        }
-
-        let data = await DataService.getInvitesData(useDev, userId);
-
-        res.status(200).send(data);
-    } catch (e) {
-        logger.error('Error handling a request: ' + e.message);
-        res.status(500).send({'message': 'Internal Server Error. Try again later.'});
-    }
-});
diff --git a/src/models/partyplaner/data/data.service.ts b/src/models/partyplaner/data/data.service.ts
deleted file mode 100644
index 3c1962c..0000000
--- a/src/models/partyplaner/data/data.service.ts
+++ /dev/null
@@ -1,349 +0,0 @@
-import * as dotenv from 'dotenv';
-
-dotenv.config();
-
-const mariadb = require('mariadb');
-const prod_pool = mariadb.createPool({
-    host: process.env.DB_HOST,
-    user: process.env.DB_USER,
-    password: process.env.DB_PASSWORD,
-    database: process.env.PARTYPLANER_PROD_DATABASE,
-    connectionLimit: 5
-});
-const dev_pool = mariadb.createPool({
-    host: process.env.DB_HOST,
-    user: process.env.DB_USER,
-    password: process.env.DB_PASSWORD,
-    database: process.env.PARTYPLANER_DEV_DATABASE,
-    connectionLimit: 5
-});
-
-/**
- * Used in the getUserData method as return value
- */
-export interface UserData {
-    username: string;
-    email: string;
-    firstName: string;
-    lastName: string;
-    lastLogin: string;
-    emailIsVerified: string;
-    isPremiumUser: string;
-}
-
-/**
- * Used in the getSessionData method as return value
- */
-export interface SessionData {
-    sessionId: string;
-    type: string;
-    lastLogin: string;
-    lastIp: string;
-}
-
-/**
- * Used in the getFriendshipData method as a return value
- */
-export interface Friendship {
-    friendshipId: string;
-    friendId: string;
-    friendFirstName: string;
-    friendLastName: string;
-    friendUsername: string;
-}
-
-/**
- * Used in the getEventData method
- */
-export interface Invite {
-    inviteId: string;
-    inviteKey: string;
-    validUntil: Date;
-    alreadyUsed: boolean;
-    invitedPersonName: string;
-}
-
-/**
- * Used in the getEventData method
- */
-export interface Registration {
-    registrationId: string;
-    name: string;
-    registeredDate: Date;
-    takesPart: boolean;
-    comment: string;
-}
-
-/**
- * Used in the getEventData method as a return value
- */
-export interface Event {
-    eventId: string;
-    name: string;
-    description: string;
-    takesPlaceDate: Date;
-    registrationUntilDate: Date;
-    maxParticipants: number;
-    invites: Invite[];
-    registrations: Registration[];
-}
-
-/**
- * Used in the getInvitesData method as a return value
- */
-export interface ReceivedInvite {
-    inviteId: string;
-    validUntil: Date;
-    alreadyUsed: boolean;
-    inviteKey: string;
-    eventName: string;
-    eventDescription: string;
-    takesPlaceDate: Date;
-    registrationUntilDate: Date;
-    maxParticipants: number;
-    eventCreatorId: string;
-    creatorFirstName: string;
-    creatorLastName: string;
-}
-
-/**
- * Returns all data about the given user
- * @param useDev If the dev or prod database should be used
- * @param userId The userId of the user to return the data for
- * @return UserData An object containing the user data
- */
-export const getUserData = async (useDev: boolean, userId: string): Promise<UserData> => {
-    let conn;
-    try {
-        if (useDev) {
-            conn = await dev_pool.getConnection();
-        } else {
-            conn = await prod_pool.getConnection();
-        }
-
-        let rows = await conn.query('SELECT username, email, first_name, last_Name, last_login, email_is_verified, is_premium_user FROM users WHERE user_id = ?', userId);
-
-        let user: UserData = {} as UserData;
-
-        for (let row of rows) {
-            user = {
-                username: row.username,
-                email: row.email,
-                firstName: row.first_name,
-                lastName: row.last_name,
-                lastLogin: row.last_login,
-                emailIsVerified: row.email_is_verified,
-                isPremiumUser: row.is_premium_user
-            };
-        }
-
-        return user;
-    } catch (err) {
-        throw err;
-    } finally {
-        if (conn) {
-            conn.end();
-        }
-    }
-};
-
-/**
- * Returns all active sessions of the given user
- * @param useDev If the dev or prod database should be used
- * @param userId The userId of the user to return the sessions for
- * @return SessionData[] A list containing objects with the session data
- */
-export const getSessionData = async (useDev: boolean, userId: string): Promise<SessionData[]> => {
-    let conn;
-    try {
-        if (useDev) {
-            conn = await dev_pool.getConnection();
-        } else {
-            conn = await prod_pool.getConnection();
-        }
-
-        let rows = await conn.query('SELECT session_id, type, last_login, last_ip FROM sessions WHERE user_id = ? AND valid_until > NOW()', userId);
-
-        let sessions: SessionData[] = [];
-
-        for (let row of rows) {
-            sessions.push({
-                sessionId: row.session_id,
-                type: row.type,
-                lastLogin: row.last_login,
-                lastIp: row.last_ip
-            });
-        }
-
-        return sessions;
-    } catch (err) {
-        throw err;
-    } finally {
-        if (conn) {
-            conn.end();
-        }
-    }
-};
-
-/**
- * Returns all friends of the given user
- * @param useDev If the dev or prod database should be used
- * @param userId The userId of the user to fetch the friends for
- * @return Friendship[] A list of friends
- */
-export const getFriendshipData = async (useDev: boolean, userId: string): Promise<Friendship[]> => {
-    let conn;
-    try {
-        if (useDev) {
-            conn = await dev_pool.getConnection();
-        } else {
-            conn = await prod_pool.getConnection();
-        }
-
-        let rows = await conn.query('SELECT f.friendship_id, f.friend_id, u.first_name as friend_first_name, u.last_name as friend_last_name, u.username as friend_username FROM friendships f LEFT OUTER JOIN users u ON f.friend_id = u.user_id WHERE f.user_id = ?', userId);
-
-        let friends: Friendship[] = [];
-
-        for (let row of rows) {
-            friends.push({
-                friendshipId: row.friendship_id,
-                friendId: row.friend_id,
-                friendFirstName: row.friend_first_name,
-                friendLastName: row.friend_last_name,
-                friendUsername: row.friend_username
-            });
-        }
-
-        return friends;
-    } catch (err) {
-        throw err;
-    } finally {
-        if (conn) {
-            conn.end();
-        }
-    }
-};
-
-/**
- * Returns all events of the given user
- * @param useDev If the dev or prod database should be used
- * @param userId The userId of the user to fetch the friends for
- * @return Event[] A list of events
- */
-export const getEventData = async (useDev: boolean, userId: string): Promise<Event[]> => {
-    let conn;
-    try {
-        if (useDev) {
-            conn = await dev_pool.getConnection();
-        } else {
-            conn = await prod_pool.getConnection();
-        }
-
-        let eventRows = await conn.query('SELECT event_id, name, description, takes_place_date, registration_until_date, max_participants FROM events WHERE creator_id = ?', userId);
-
-        let eventsMap = new Map<string, Event>();
-        let eventIds: string[] = [];
-
-        for (let row of eventRows) {
-            eventIds.push(row.event_id);
-            let event = {
-                eventId: row.event_id,
-                name: row.name,
-                description: row.description,
-                takesPlaceDate: row.takes_place_date,
-                registrationUntilDate: row.registration_until_date,
-                maxParticipants: row.max_participants,
-                invites: [],
-                registrations: []
-            };
-            eventsMap.set(row.event_id, event);
-        }
-
-        let registrationRows = await conn.query('SELECT registration_id, name, registered_date, takes_part, comment, event_id FROM event_registration WHERE event_id IN (?)', eventIds);
-
-        for (let row of registrationRows) {
-            let event = eventsMap.get(row.event_id);
-            if (!event) continue;
-            event.registrations.push({
-                registrationId: row.registration_id,
-                name: row.name,
-                registeredDate: row.registered_date,
-                takesPart: row.takes_part,
-                comment: row.comment
-            });
-        }
-
-        let inviteRows = await conn.query('SELECT invite_id, invite_key, valid_until, already_used, invited_person_name, event_id FROM invitations WHERE event_id IN (?)', eventIds);
-
-        for (let row of inviteRows) {
-            let event = eventsMap.get(row.event_id);
-            if (!event) continue;
-            event.invites.push({
-                inviteId: row.invite_id,
-                inviteKey: row.invite_key,
-                validUntil: row.valid_until,
-                alreadyUsed: row.already_used,
-                invitedPersonName: row.invited_person_name
-            });
-        }
-
-        let eventsList: Event[] = [];
-        for (let event of eventsMap.values()) {
-            eventsList.push(event);
-        }
-
-        return eventsList;
-    } catch (err) {
-        throw err;
-    } finally {
-        if (conn) {
-            conn.end();
-        }
-    }
-};
-
-/**
- * Returns all events the user is invited to
- * @param useDev If the dev or prod database should be used
- * @param userId The userId of the user to fetch the friends for
- * @return ReceivedInvite[] A list of invites
- */
-export const getInvitesData = async (useDev: boolean, userId: string): Promise<ReceivedInvite[]> => {
-    let conn;
-    try {
-        if (useDev) {
-            conn = await dev_pool.getConnection();
-        } else {
-            conn = await prod_pool.getConnection();
-        }
-
-        let rows = await conn.query('SELECT i.invite_id, i.valid_until, i.already_used, i.invite_key, e.name as event_name, e.description as event_description, e.takes_place_date, e.registration_until_date, e.max_participants, e.creator_id, u.first_name, u.last_name FROM invitations i LEFT OUTER JOIN events e ON e.event_id = i.event_id LEFT OUTER JOIN users u ON u.user_id = e.creator_id WHERE i.user_id = ?', userId);
-
-        let invites: ReceivedInvite[] = [];
-
-        for (let row of rows) {
-            invites.push({
-                inviteId: row.invite_id,
-                validUntil: row.valid_until,
-                alreadyUsed: row.already_used,
-                inviteKey: row.invite_key,
-                eventName: row.event_name,
-                eventDescription: row.event_description,
-                takesPlaceDate: row.takes_place_date,
-                registrationUntilDate: row.registration_until_date,
-                maxParticipants: row.max_participants,
-                eventCreatorId: row.creator_id,
-                creatorFirstName: row.first_name,
-                creatorLastName: row.last_name
-            });
-        }
-
-        return invites;
-    } catch (err) {
-        throw err;
-    } finally {
-        if (conn) {
-            conn.end();
-        }
-    }
-};
diff --git a/src/models/partyplaner/event/Event.interface.ts b/src/models/partyplaner/event/Event.interface.ts
new file mode 100644
index 0000000..14c3a7d
--- /dev/null
+++ b/src/models/partyplaner/event/Event.interface.ts
@@ -0,0 +1,16 @@
+import {Invite} from './Invite.interface';
+import {Registration} from './Registration.interface';
+
+/**
+ * Used in the getEventData method as a return value
+ */
+export interface Event {
+    eventId: string;
+    name: string;
+    description: string;
+    takesPlaceDate: Date;
+    registrationUntilDate: Date;
+    maxParticipants: number;
+    invites: Invite[];
+    registrations: Registration[];
+}
diff --git a/src/models/partyplaner/event/Event.router.ts b/src/models/partyplaner/event/Event.router.ts
new file mode 100644
index 0000000..e3dd304
--- /dev/null
+++ b/src/models/partyplaner/event/Event.router.ts
@@ -0,0 +1,44 @@
+/**
+ * Required External Modules and Interfaces
+ */
+import express, {Request, Response} from 'express';
+import * as EventService from './event.service';
+import * as UserService from '../user/user.service';
+import logger from '../../../middleware/logger';
+
+/**
+ * Router Definition
+ */
+export const eventRouter = express.Router();
+
+eventRouter.get('/:isDevCall', async (req: Request, res: Response) => {
+    try {
+        let userId = (req.query.userId ?? '').toString();
+        let sessionId = (req.query.sessionId ?? '').toString();
+        let sessionKey = (req.query.sessionKey ?? '').toString();
+        let useDev: boolean = (req.params.isDevCall ?? '') === 'dev'; // TBD
+
+        if (userId === '' || sessionId === '' || sessionKey === '') {
+            res.status(400).send({
+                'status': 'WRONG_PARAMS',
+                'message': 'Missing or wrong parameters'
+            });
+            return;
+        }
+
+        if (!await UserService.checkSession(useDev, userId, sessionId, sessionKey)) {
+            res.status(403).send({
+                'status': 'INVALID_SESSION',
+                'message': 'The user or session could not be found or the session is invalid'
+            });
+            return;
+        }
+
+        let data = await EventService.getEventData(useDev, userId);
+
+        res.status(200).send(data);
+    } catch (e) {
+        logger.error('Error handling a request: ' + e.message);
+        res.status(500).send({'message': 'Internal Server Error. Try again later.'});
+    }
+});
diff --git a/src/models/partyplaner/event/Invite.interface.ts b/src/models/partyplaner/event/Invite.interface.ts
new file mode 100644
index 0000000..e4ecd8c
--- /dev/null
+++ b/src/models/partyplaner/event/Invite.interface.ts
@@ -0,0 +1,10 @@
+/**
+ * Used in the getEventData method
+ */
+export interface Invite {
+    inviteId: string;
+    inviteKey: string;
+    validUntil: Date;
+    alreadyUsed: boolean;
+    invitedPersonName: string;
+}
diff --git a/src/models/partyplaner/event/Registration.interface.ts b/src/models/partyplaner/event/Registration.interface.ts
new file mode 100644
index 0000000..207b40e
--- /dev/null
+++ b/src/models/partyplaner/event/Registration.interface.ts
@@ -0,0 +1,10 @@
+/**
+ * Used in the getEventData method
+ */
+export interface Registration {
+    registrationId: string;
+    name: string;
+    registeredDate: Date;
+    takesPart: boolean;
+    comment: string;
+}
diff --git a/src/models/partyplaner/event/event.service.ts b/src/models/partyplaner/event/event.service.ts
new file mode 100644
index 0000000..a32f31f
--- /dev/null
+++ b/src/models/partyplaner/event/event.service.ts
@@ -0,0 +1,98 @@
+import * as dotenv from 'dotenv';
+import {Event} from './event.interface';
+
+dotenv.config();
+
+const mariadb = require('mariadb');
+const prod_pool = mariadb.createPool({
+    host: process.env.DB_HOST,
+    user: process.env.DB_USER,
+    password: process.env.DB_PASSWORD,
+    database: process.env.PARTYPLANER_PROD_DATABASE,
+    connectionLimit: 5
+});
+const dev_pool = mariadb.createPool({
+    host: process.env.DB_HOST,
+    user: process.env.DB_USER,
+    password: process.env.DB_PASSWORD,
+    database: process.env.PARTYPLANER_DEV_DATABASE,
+    connectionLimit: 5
+});
+
+/**
+ * Returns all events of the given user
+ * @param useDev If the dev or prod database should be used
+ * @param userId The userId of the user to fetch the friends for
+ * @return Event[] A list of events
+ */
+export const getEventData = async (useDev: boolean, userId: string): Promise<Event[]> => {
+    let conn;
+    try {
+        if (useDev) {
+            conn = await dev_pool.getConnection();
+        } else {
+            conn = await prod_pool.getConnection();
+        }
+
+        let eventRows = await conn.query('SELECT event_id, name, description, takes_place_date, registration_until_date, max_participants FROM events WHERE creator_id = ?', userId);
+
+        let eventsMap = new Map<string, Event>();
+        let eventIds: string[] = [];
+
+        for (let row of eventRows) {
+            eventIds.push(row.event_id);
+            let event = {
+                eventId: row.event_id,
+                name: row.name,
+                description: row.description,
+                takesPlaceDate: row.takes_place_date,
+                registrationUntilDate: row.registration_until_date,
+                maxParticipants: row.max_participants,
+                invites: [],
+                registrations: []
+            };
+            eventsMap.set(row.event_id, event);
+        }
+
+        let registrationRows = await conn.query('SELECT registration_id, name, registered_date, takes_part, comment, event_id FROM event_registration WHERE event_id IN (?)', eventIds);
+
+        for (let row of registrationRows) {
+            let event = eventsMap.get(row.event_id);
+            if (!event) continue;
+            event.registrations.push({
+                registrationId: row.registration_id,
+                name: row.name,
+                registeredDate: row.registered_date,
+                takesPart: row.takes_part,
+                comment: row.comment
+            });
+        }
+
+        let inviteRows = await conn.query('SELECT invite_id, invite_key, valid_until, already_used, invited_person_name, event_id FROM invitations WHERE event_id IN (?)', eventIds);
+
+        for (let row of inviteRows) {
+            let event = eventsMap.get(row.event_id);
+            if (!event) continue;
+            event.invites.push({
+                inviteId: row.invite_id,
+                inviteKey: row.invite_key,
+                validUntil: row.valid_until,
+                alreadyUsed: row.already_used,
+                invitedPersonName: row.invited_person_name
+            });
+        }
+
+        let eventsList: Event[] = [];
+        for (let event of eventsMap.values()) {
+            eventsList.push(event);
+        }
+
+        return eventsList;
+    } catch (err) {
+        throw err;
+    } finally {
+        if (conn) {
+            conn.end();
+        }
+    }
+};
diff --git a/src/models/partyplaner/friendship/Friendship.interface.ts b/src/models/partyplaner/friendship/Friendship.interface.ts
new file mode 100644
index 0000000..5d4e6ca
--- /dev/null
+++ b/src/models/partyplaner/friendship/Friendship.interface.ts
@@ -0,0 +1,10 @@
+/**
+ * Used in the getFriendshipData method as a return value
+ */
+export interface Friendship {
+    friendshipId: string;
+    friendId: string;
+    friendFirstName: string;
+    friendLastName: string;
+    friendUsername: string;
+}
diff --git a/src/models/partyplaner/friendship/Friendship.router.ts b/src/models/partyplaner/friendship/Friendship.router.ts
new file mode 100644
index 0000000..e172418
--- /dev/null
+++ b/src/models/partyplaner/friendship/Friendship.router.ts
@@ -0,0 +1,44 @@
+/**
+ * Required External Modules and Interfaces
+ */
+import express, {Request, Response} from 'express';
+import * as FriendshipService from './friendship.service';
+import * as UserService from '../user/user.service';
+import logger from '../../../middleware/logger';
+
+/**
+ * Router Definition
+ */
+export const friendshipRouter = express.Router();
+
+friendshipRouter.get('/:isDevCall', async (req: Request, res: Response) => {
+    try {
+        let userId = (req.query.userId ?? '').toString();
+        let sessionId = (req.query.sessionId ?? '').toString();
+        let sessionKey = (req.query.sessionKey ?? '').toString();
+        let useDev: boolean = (req.params.isDevCall ?? '') === 'dev'; // TBD
+
+        if (userId === '' || sessionId === '' || sessionKey === '') {
+            res.status(400).send({
+                'status': 'WRONG_PARAMS',
+                'message': 'Missing or wrong parameters'
+            });
+            return;
+        }
+
+        if (!await UserService.checkSession(useDev, userId, sessionId, sessionKey)) {
+            res.status(403).send({
+                'status': 'INVALID_SESSION',
+                'message': 'The user or session could not be found or the session is invalid'
+            });
+            return;
+        }
+
+        let data = await FriendshipService.getFriendshipData(useDev, userId);
+
+        res.status(200).send(data);
+    } catch (e) {
+        logger.error('Error handling a request: ' + e.message);
+        res.status(500).send({'message': 'Internal Server Error. Try again later.'});
+    }
+});
diff --git a/src/models/partyplaner/friendship/friendship.service.ts b/src/models/partyplaner/friendship/friendship.service.ts
new file mode 100644
index 0000000..9a2a8fe
--- /dev/null
+++ b/src/models/partyplaner/friendship/friendship.service.ts
@@ -0,0 +1,59 @@
+import * as dotenv from 'dotenv';
+import {Friendship} from './Friendship.interface';
+
+dotenv.config();
+
+const mariadb = require('mariadb');
+const prod_pool = mariadb.createPool({
+    host: process.env.DB_HOST,
+    user: process.env.DB_USER,
+    password: process.env.DB_PASSWORD,
+    database: process.env.PARTYPLANER_PROD_DATABASE,
+    connectionLimit: 5
+});
+const dev_pool = mariadb.createPool({
+    host: process.env.DB_HOST,
+    user: process.env.DB_USER,
+    password: process.env.DB_PASSWORD,
+    database: process.env.PARTYPLANER_DEV_DATABASE,
+    connectionLimit: 5
+});
+
+/**
+ * Returns all friends of the given user
+ * @param useDev If the dev or prod database should be used
+ * @param userId The userId of the user to fetch the friends for
+ * @return Friendship[] A list of friends
+ */
+export const getFriendshipData = async (useDev: boolean, userId: string): Promise<Friendship[]> => {
+    let conn;
+    try {
+        if (useDev) {
+            conn = await dev_pool.getConnection();
+        } else {
+            conn = await prod_pool.getConnection();
+        }
+
+        let rows = await conn.query('SELECT f.friendship_id, f.friend_id, u.first_name as friend_first_name, u.last_name as friend_last_name, u.username as friend_username FROM friendships f LEFT OUTER JOIN users u ON f.friend_id = u.user_id WHERE f.user_id = ?', userId);
+
+        let friends: Friendship[] = [];
+
+        for (let row of rows) {
+            friends.push({
+                friendshipId: row.friendship_id,
+                friendId: row.friend_id,
+                friendFirstName: row.friend_first_name,
+                friendLastName: row.friend_last_name,
+                friendUsername: row.friend_username
+            });
+        }
+
+        return friends;
+    } catch (err) {
+        throw err;
+    } finally {
+        if (conn) {
+            conn.end();
+        }
+    }
+};
diff --git a/src/models/partyplaner/invite/Invite.router.ts b/src/models/partyplaner/invite/Invite.router.ts
new file mode 100644
index 0000000..e006f80
--- /dev/null
+++ b/src/models/partyplaner/invite/Invite.router.ts
@@ -0,0 +1,44 @@
+/**
+ * Required External Modules and Interfaces
+ */
+import express, {Request, Response} from 'express';
+import * as InviteService from './invite.service';
+import * as UserService from '../user/user.service';
+import logger from '../../../middleware/logger';
+
+/**
+ * Router Definition
+ */
+export const inviteRouter = express.Router();
+
+inviteRouter.get('/:isDevCall', async (req: Request, res: Response) => {
+    try {
+        let userId = (req.query.userId ?? '').toString();
+        let sessionId = (req.query.sessionId ?? '').toString();
+        let sessionKey = (req.query.sessionKey ?? '').toString();
+        let useDev: boolean = (req.params.isDevCall ?? '') === 'dev'; // TBD
+
+        if (userId === '' || sessionId === '' || sessionKey === '') {
+            res.status(400).send({
+                'status': 'WRONG_PARAMS',
+                'message': 'Missing or wrong parameters'
+            });
+            return;
+        }
+
+        if (!await UserService.checkSession(useDev, userId, sessionId, sessionKey)) {
+            res.status(403).send({
+                'status': 'INVALID_SESSION',
+                'message': 'The user or session could not be found or the session is invalid'
+            });
+            return;
+        }
+
+        let data = await InviteService.getInvitesData(useDev, userId);
+
+        res.status(200).send(data);
+    } catch (e) {
+        logger.error('Error handling a request: ' + e.message);
+        res.status(500).send({'message': 'Internal Server Error. Try again later.'});
+    }
+});
diff --git a/src/models/partyplaner/invite/ReceivedInvite.interface.ts b/src/models/partyplaner/invite/ReceivedInvite.interface.ts
new file mode 100644
index 0000000..322ce68
--- /dev/null
+++ b/src/models/partyplaner/invite/ReceivedInvite.interface.ts
@@ -0,0 +1,17 @@
+/**
+ * Used in the getInvitesData method as a return value
+ */
+export interface ReceivedInvite {
+    inviteId: string;
+    validUntil: Date;
+    alreadyUsed: boolean;
+    inviteKey: string;
+    eventName: string;
+    eventDescription: string;
+    takesPlaceDate: Date;
+    registrationUntilDate: Date;
+    maxParticipants: number;
+    eventCreatorId: string;
+    creatorFirstName: string;
+    creatorLastName: string;
+}
diff --git a/src/models/partyplaner/invite/invite.service.ts b/src/models/partyplaner/invite/invite.service.ts
new file mode 100644
index 0000000..c7934bf
--- /dev/null
+++ b/src/models/partyplaner/invite/invite.service.ts
@@ -0,0 +1,66 @@
+import * as dotenv from 'dotenv';
+import {ReceivedInvite} from './ReceivedInvite.interface';
+
+dotenv.config();
+
+const mariadb = require('mariadb');
+const prod_pool = mariadb.createPool({
+    host: process.env.DB_HOST,
+    user: process.env.DB_USER,
+    password: process.env.DB_PASSWORD,
+    database: process.env.PARTYPLANER_PROD_DATABASE,
+    connectionLimit: 5
+});
+const dev_pool = mariadb.createPool({
+    host: process.env.DB_HOST,
+    user: process.env.DB_USER,
+    password: process.env.DB_PASSWORD,
+    database: process.env.PARTYPLANER_DEV_DATABASE,
+    connectionLimit: 5
+});
+
+/**
+ * Returns all events the user is invited to
+ * @param useDev If the dev or prod database should be used
+ * @param userId The userId of the user to fetch the friends for
+ * @return ReceivedInvite[] A list of invites
+ */
+export const getInvitesData = async (useDev: boolean, userId: string): Promise<ReceivedInvite[]> => {
+    let conn;
+    try {
+        if (useDev) {
+            conn = await dev_pool.getConnection();
+        } else {
+            conn = await prod_pool.getConnection();
+        }
+
+        let rows = await conn.query('SELECT i.invite_id, i.valid_until, i.already_used, i.invite_key, e.name as event_name, e.description as event_description, e.takes_place_date, e.registration_until_date, e.max_participants, e.creator_id, u.first_name, u.last_name FROM invitations i LEFT OUTER JOIN events e ON e.event_id = i.event_id LEFT OUTER JOIN users u ON u.user_id = e.creator_id WHERE i.user_id = ?', userId);
+
+        let invites: ReceivedInvite[] = [];
+
+        for (let row of rows) {
+            invites.push({
+                inviteId: row.invite_id,
+                validUntil: row.valid_until,
+                alreadyUsed: row.already_used,
+                inviteKey: row.invite_key,
+                eventName: row.event_name,
+                eventDescription: row.event_description,
+                takesPlaceDate: row.takes_place_date,
+                registrationUntilDate: row.registration_until_date,
+                maxParticipants: row.max_participants,
+                eventCreatorId: row.creator_id,
+                creatorFirstName: row.first_name,
+                creatorLastName: row.last_name
+            });
+        }
+
+        return invites;
+    } catch (err) {
+        throw err;
+    } finally {
+        if (conn) {
+            conn.end();
+        }
+    }
+};
diff --git a/src/models/partyplaner/login/Login.router.ts b/src/models/partyplaner/login/Login.router.ts
index 191127a..46537d0 100644
--- a/src/models/partyplaner/login/Login.router.ts
+++ b/src/models/partyplaner/login/Login.router.ts
@@ -2,7 +2,7 @@
  * Required External Modules and Interfaces
  */
 import express, {Request, Response} from 'express';
-import * as UserService from '../userService/user.service';
+import * as UserService from '../user/user.service';
 import logger from '../../../middleware/logger';
 
 /**
diff --git a/src/models/partyplaner/register/Register.router.ts b/src/models/partyplaner/register/Register.router.ts
index 25ddd21..786c1c1 100644
--- a/src/models/partyplaner/register/Register.router.ts
+++ b/src/models/partyplaner/register/Register.router.ts
@@ -2,7 +2,7 @@
  * Required External Modules and Interfaces
  */
 import express, {Request, Response} from 'express';
-import * as UserService from '../userService/user.service';
+import * as UserService from '../user/user.service';
 import logger from '../../../middleware/logger';
 
 /**
diff --git a/src/models/partyplaner/session/Session.router.ts b/src/models/partyplaner/session/Session.router.ts
new file mode 100644
index 0000000..73dd3cb
--- /dev/null
+++ b/src/models/partyplaner/session/Session.router.ts
@@ -0,0 +1,44 @@
+/**
+ * Required External Modules and Interfaces
+ */
+import express, {Request, Response} from 'express';
+import * as SessionService from './session.service';
+import * as UserService from '../user/user.service';
+import logger from '../../../middleware/logger';
+
+/**
+ * Router Definition
+ */
+export const sessionRouter = express.Router();
+
+sessionRouter.get('/:isDevCall', async (req: Request, res: Response) => {
+    try {
+        let userId = (req.query.userId ?? '').toString();
+        let sessionId = (req.query.sessionId ?? '').toString();
+        let sessionKey = (req.query.sessionKey ?? '').toString();
+        let useDev: boolean = (req.params.isDevCall ?? '') === 'dev'; // TBD
+
+        if (userId === '' || sessionId === '' || sessionKey === '') {
+            res.status(400).send({
+                'status': 'WRONG_PARAMS',
+                'message': 'Missing or wrong parameters'
+            });
+            return;
+        }
+
+        if (!await UserService.checkSession(useDev, userId, sessionId, sessionKey)) {
+            res.status(403).send({
+                'status': 'INVALID_SESSION',
+                'message': 'The user or session could not be found or the session is invalid'
+            });
+            return;
+        }
+
+        let data = await SessionService.getSessionData(useDev, userId);
+
+        res.status(200).send(data);
+    } catch (e) {
+        logger.error('Error handling a request: ' + e.message);
+        res.status(500).send({'message': 'Internal Server Error. Try again later.'});
+    }
+});
diff --git a/src/models/partyplaner/session/SessionData.interface.ts b/src/models/partyplaner/session/SessionData.interface.ts
new file mode 100644
index 0000000..8c8cbd2
--- /dev/null
+++ b/src/models/partyplaner/session/SessionData.interface.ts
@@ -0,0 +1,9 @@
+/**
+ * Used in the getSessionData method as return value
+ */
+export interface SessionData {
+    sessionId: string;
+    type: string;
+    lastLogin: string;
+    lastIp: string;
+}
diff --git a/src/models/partyplaner/session/session.service.ts b/src/models/partyplaner/session/session.service.ts
new file mode 100644
index 0000000..327e270
--- /dev/null
+++ b/src/models/partyplaner/session/session.service.ts
@@ -0,0 +1,58 @@
+import * as dotenv from 'dotenv';
+import {SessionData} from './SessionData.interface';
+
+dotenv.config();
+
+const mariadb = require('mariadb');
+const prod_pool = mariadb.createPool({
+    host: process.env.DB_HOST,
+    user: process.env.DB_USER,
+    password: process.env.DB_PASSWORD,
+    database: process.env.PARTYPLANER_PROD_DATABASE,
+    connectionLimit: 5
+});
+const dev_pool = mariadb.createPool({
+    host: process.env.DB_HOST,
+    user: process.env.DB_USER,
+    password: process.env.DB_PASSWORD,
+    database: process.env.PARTYPLANER_DEV_DATABASE,
+    connectionLimit: 5
+});
+
+/**
+ * Returns all active sessions of the given user
+ * @param useDev If the dev or prod database should be used
+ * @param userId The userId of the user to return the sessions for
+ * @return SessionData[] A list containing objects with the session data
+ */
+export const getSessionData = async (useDev: boolean, userId: string): Promise<SessionData[]> => {
+    let conn;
+    try {
+        if (useDev) {
+            conn = await dev_pool.getConnection();
+        } else {
+            conn = await prod_pool.getConnection();
+        }
+
+        let rows = await conn.query('SELECT session_id, type, last_login, last_ip FROM sessions WHERE user_id = ? AND valid_until > NOW()', userId);
+
+        let sessions: SessionData[] = [];
+
+        for (let row of rows) {
+            sessions.push({
+                sessionId: row.session_id,
+                type: row.type,
+                lastLogin: row.last_login,
+                lastIp: row.last_ip
+            });
+        }
+
+        return sessions;
+    } catch (err) {
+        throw err;
+    } finally {
+        if (conn) {
+            conn.end();
+        }
+    }
+};
diff --git a/src/models/partyplaner/user/Session.interface.ts b/src/models/partyplaner/user/Session.interface.ts
new file mode 100644
index 0000000..048c6ec
--- /dev/null
+++ b/src/models/partyplaner/user/Session.interface.ts
@@ -0,0 +1,8 @@
+/**
+ * Used in the registerUser and loginUser methods as return value
+ */
+export interface Session {
+    userId: string;
+    sessionId: string;
+    sessionKey: string;
+}
diff --git a/src/models/partyplaner/user/Status.interface.ts b/src/models/partyplaner/user/Status.interface.ts
new file mode 100644
index 0000000..8b0e3f8
--- /dev/null
+++ b/src/models/partyplaner/user/Status.interface.ts
@@ -0,0 +1,8 @@
+/**
+ * Used in the checkUsernameAndEmail method as return value
+ */
+export interface Status {
+    hasProblems: boolean;
+    messages: string[];
+    status: string[];
+}
diff --git a/src/models/partyplaner/user/User.router.ts b/src/models/partyplaner/user/User.router.ts
new file mode 100644
index 0000000..c7173e0
--- /dev/null
+++ b/src/models/partyplaner/user/User.router.ts
@@ -0,0 +1,43 @@
+/**
+ * Required External Modules and Interfaces
+ */
+import express, {Request, Response} from 'express';
+import * as UserService from './user.service';
+import logger from '../../../middleware/logger';
+
+/**
+ * Router Definition
+ */
+export const userRouter = express.Router();
+
+userRouter.get('/:isDevCall', async (req: Request, res: Response) => {
+    try {
+        let userId = (req.query.userId ?? '').toString();
+        let sessionId = (req.query.sessionId ?? '').toString();
+        let sessionKey = (req.query.sessionKey ?? '').toString();
+        let useDev: boolean = (req.params.isDevCall ?? '') === 'dev'; // TBD
+
+        if (userId === '' || sessionId === '' || sessionKey === '') {
+            res.status(400).send({
+                'status': 'WRONG_PARAMS',
+                'message': 'Missing or wrong parameters'
+            });
+            return;
+        }
+
+        if (!await UserService.checkSession(useDev, userId, sessionId, sessionKey)) {
+            res.status(403).send({
+                'status': 'INVALID_SESSION',
+                'message': 'The user or session could not be found or the session is invalid'
+            });
+            return;
+        }
+
+        let data = await UserService.getUserData(useDev, userId);
+
+        res.status(200).send(data);
+    } catch (e) {
+        logger.error('Error handling a request: ' + e.message);
+        res.status(500).send({'message': 'Internal Server Error. Try again later.'});
+    }
+});
diff --git a/src/models/partyplaner/user/UserData.interface.ts b/src/models/partyplaner/user/UserData.interface.ts
new file mode 100644
index 0000000..9c8b27c
--- /dev/null
+++ b/src/models/partyplaner/user/UserData.interface.ts
@@ -0,0 +1,12 @@
+/**
+ * Used in the getUserData method as return value
+ */
+export interface UserData {
+    username: string;
+    email: string;
+    firstName: string;
+    lastName: string;
+    lastLogin: string;
+    emailIsVerified: string;
+    isPremiumUser: string;
+}
diff --git a/src/models/partyplaner/userService/user.service.ts b/src/models/partyplaner/user/user.service.ts
similarity index 88%
rename from src/models/partyplaner/userService/user.service.ts
rename to src/models/partyplaner/user/user.service.ts
index c31d09c..55f2236 100644
--- a/src/models/partyplaner/userService/user.service.ts
+++ b/src/models/partyplaner/user/user.service.ts
@@ -1,6 +1,9 @@
 import * as dotenv from 'dotenv';
 import * as bcrypt from 'bcrypt';
 import {Guid} from 'guid-typescript';
+import {UserData} from './UserData.interface';
+import {Session} from './Session.interface';
+import {Status} from './Status.interface';
 
 dotenv.config();
 
@@ -21,22 +24,45 @@ const dev_pool = mariadb.createPool({
 });
 
 /**
- * Used in the registerUser and loginUser methods as return value
+ * Returns all data about the given user
+ * @param useDev If the dev or prod database should be used
+ * @param userId The userId of the user to return the data for
+ * @return UserData An object containing the user data
  */
-export interface Session {
-    userId: string;
-    sessionId: string;
-    sessionKey: string;
-}
+export const getUserData = async (useDev: boolean, userId: string): Promise<UserData> => {
+    let conn;
+    try {
+        if (useDev) {
+            conn = await dev_pool.getConnection();
+        } else {
+            conn = await prod_pool.getConnection();
+        }
 
-/**
- * Used in the checkUsernameAndEmail method as return value
- */
-export interface Status {
-    hasProblems: boolean;
-    messages: string[];
-    status: string[];
-}
+        let rows = await conn.query('SELECT username, email, first_name, last_Name, last_login, email_is_verified, is_premium_user FROM users WHERE user_id = ?', userId);
+
+        let user: UserData = {} as UserData;
+
+        for (let row of rows) {
+            user = {
+                username: row.username,
+                email: row.email,
+                firstName: row.first_name,
+                lastName: row.last_name,
+                lastLogin: row.last_login,
+                emailIsVerified: row.email_is_verified,
+                isPremiumUser: row.is_premium_user
+            };
+        }
+
+        return user;
+    } catch (err) {
+        throw err;
+    } finally {
+        if (conn) {
+            conn.end();
+        }
+    }
+};
 
 /**
  * Fetches all usernames and emails from the database and returns them in an object