diff --git a/.eslintrc.js b/.eslintrc.js
index 16a57233e..0d821dc32 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -12,6 +12,7 @@ module.exports = {
   extends: [
     'eslint:recommended',
     'plugin:@typescript-eslint/recommended',
+    'plugin:@typescript-eslint/recommended-requiring-type-checking',
     'prettier',
   ],
   root: true,
@@ -20,13 +21,37 @@ module.exports = {
     jest: true,
   },
   rules: {
-    '@typescript-eslint/interface-name-prefix': 'off',
-    '@typescript-eslint/explicit-function-return-type': 'off',
-    '@typescript-eslint/no-explicit-any': 'off',
+    'func-style': ['error', 'declaration'],
     '@typescript-eslint/no-unused-vars': [
       'warn',
       { argsIgnorePattern: '^_+$' },
     ],
-    '@typescript-eslint/explicit-module-boundary-types': 'off',
+    '@typescript-eslint/explicit-function-return-type': 'warn',
+    'no-return-await': 'off',
+    '@typescript-eslint/return-await': ['error', 'always'],
+    '@typescript-eslint/naming-convention': [
+      'error',
+      {
+        selector: 'default',
+        format: ['camelCase'],
+        leadingUnderscore: 'allow',
+        trailingUnderscore: 'allow',
+      },
+      {
+        selector: 'enumMember',
+        format: ['UPPER_CASE'],
+      },
+      {
+        selector: 'variable',
+        format: ['camelCase', 'UPPER_CASE'],
+        leadingUnderscore: 'allow',
+        trailingUnderscore: 'allow',
+      },
+
+      {
+        selector: 'typeLike',
+        format: ['PascalCase'],
+      },
+    ],
   },
 };
diff --git a/package.json b/package.json
index 84060db2a..e5a9a7421 100644
--- a/package.json
+++ b/package.json
@@ -58,9 +58,11 @@
     "@nestjs/cli": "7.5.6",
     "@nestjs/schematics": "7.2.8",
     "@nestjs/testing": "7.6.13",
+    "@types/cli-color": "^2.0.0",
     "@types/express": "4.17.11",
     "@types/jest": "26.0.20",
     "@types/node": "13.13.45",
+    "@types/shortid": "^0.0.29",
     "@types/supertest": "2.0.10",
     "@typescript-eslint/eslint-plugin": "4.15.2",
     "@typescript-eslint/parser": "4.15.2",
diff --git a/src/api/private/tokens/tokens.controller.ts b/src/api/private/tokens/tokens.controller.ts
index 651982b13..d785e2ccf 100644
--- a/src/api/private/tokens/tokens.controller.ts
+++ b/src/api/private/tokens/tokens.controller.ts
@@ -44,12 +44,16 @@ export class TokensController {
     @Body('validUntil') validUntil: TimestampMillis,
   ): Promise<AuthTokenWithSecretDto> {
     // ToDo: Get real userName
-    return this.authService.createTokenForUser('hardcoded', label, validUntil);
+    return await this.authService.createTokenForUser(
+      'hardcoded',
+      label,
+      validUntil,
+    );
   }
 
   @Delete('/:keyId')
   @HttpCode(204)
-  async deleteToken(@Param('keyId') keyId: string) {
-    return this.authService.removeToken(keyId);
+  async deleteToken(@Param('keyId') keyId: string): Promise<void> {
+    return await this.authService.removeToken(keyId);
   }
 }
diff --git a/src/api/public/me/me.controller.ts b/src/api/public/me/me.controller.ts
index 89e8eef28..1169820ea 100644
--- a/src/api/public/me/me.controller.ts
+++ b/src/api/public/me/me.controller.ts
@@ -14,7 +14,7 @@ import {
   Param,
   Put,
   UseGuards,
-  Request,
+  Req,
 } from '@nestjs/common';
 import { HistoryEntryUpdateDto } from '../../../history/history-entry-update.dto';
 import { HistoryService } from '../../../history/history.service';
@@ -27,6 +27,7 @@ import { ApiSecurity, ApiTags } from '@nestjs/swagger';
 import { HistoryEntryDto } from '../../../history/history-entry.dto';
 import { UserInfoDto } from '../../../users/user-info.dto';
 import { NotInDBError } from '../../../errors/errors';
+import { Request } from 'express';
 
 @ApiTags('me')
 @ApiSecurity('token')
@@ -43,7 +44,7 @@ export class MeController {
 
   @UseGuards(TokenAuthGuard)
   @Get()
-  async getMe(@Request() req): Promise<UserInfoDto> {
+  async getMe(@Req() req: Request): Promise<UserInfoDto> {
     return this.usersService.toUserDto(
       await this.usersService.getUserByUsername(req.user.userName),
     );
@@ -51,19 +52,17 @@ export class MeController {
 
   @UseGuards(TokenAuthGuard)
   @Get('history')
-  async getUserHistory(@Request() req): Promise<HistoryEntryDto[]> {
+  async getUserHistory(@Req() req: Request): Promise<HistoryEntryDto[]> {
     const foundEntries = await this.historyService.getEntriesByUser(req.user);
-    return Promise.all(
-      foundEntries.map(
-        async (entry) => await this.historyService.toHistoryEntryDto(entry),
-      ),
+    return await Promise.all(
+      foundEntries.map((entry) => this.historyService.toHistoryEntryDto(entry)),
     );
   }
 
   @UseGuards(TokenAuthGuard)
   @Put('history/:note')
   async updateHistoryEntry(
-    @Request() req,
+    @Req() req: Request,
     @Param('note') note: string,
     @Body() entryUpdateDto: HistoryEntryUpdateDto,
   ): Promise<HistoryEntryDto> {
@@ -87,7 +86,10 @@ export class MeController {
   @UseGuards(TokenAuthGuard)
   @Delete('history/:note')
   @HttpCode(204)
-  deleteHistoryEntry(@Request() req, @Param('note') note: string) {
+  deleteHistoryEntry(
+    @Req() req: Request,
+    @Param('note') note: string,
+  ): Promise<void> {
     // ToDo: Check if user is allowed to delete note
     try {
       return this.historyService.deleteHistoryEntry(note, req.user);
@@ -101,10 +103,10 @@ export class MeController {
 
   @UseGuards(TokenAuthGuard)
   @Get('notes')
-  async getMyNotes(@Request() req): Promise<NoteMetadataDto[]> {
-    const notes = await this.notesService.getUserNotes(req.user);
-    return Promise.all(
-      notes.map((note) => this.notesService.toNoteMetadataDto(note)),
+  async getMyNotes(@Req() req: Request): Promise<NoteMetadataDto[]> {
+    const notes = this.notesService.getUserNotes(req.user);
+    return await Promise.all(
+      (await notes).map((note) => this.notesService.toNoteMetadataDto(note)),
     );
   }
 }
diff --git a/src/api/public/media/media.controller.ts b/src/api/public/media/media.controller.ts
index 4520e6b91..28fff33c3 100644
--- a/src/api/public/media/media.controller.ts
+++ b/src/api/public/media/media.controller.ts
@@ -13,13 +13,14 @@ import {
   NotFoundException,
   Param,
   Post,
-  Request,
+  Req,
   UnauthorizedException,
   UploadedFile,
   UseGuards,
   UseInterceptors,
 } from '@nestjs/common';
 import { FileInterceptor } from '@nestjs/platform-express';
+import { Request } from 'express';
 import {
   ClientError,
   MediaBackendError,
@@ -48,7 +49,7 @@ export class MediaController {
   @Post()
   @UseInterceptors(FileInterceptor('file'))
   async uploadMedia(
-    @Request() req,
+    @Req() req: Request,
     @UploadedFile() file: MulterFile,
     @Headers('HedgeDoc-Note') noteId: string,
   ): Promise<MediaUploadUrlDto> {
@@ -80,7 +81,7 @@ export class MediaController {
   @UseGuards(TokenAuthGuard)
   @Delete(':filename')
   async deleteMedia(
-    @Request() req,
+    @Req() req: Request,
     @Param('filename') filename: string,
   ): Promise<void> {
     const username = req.user.userName;
diff --git a/src/api/public/monitoring/monitoring.controller.ts b/src/api/public/monitoring/monitoring.controller.ts
index 4d561f0a3..1905adb08 100644
--- a/src/api/public/monitoring/monitoring.controller.ts
+++ b/src/api/public/monitoring/monitoring.controller.ts
@@ -25,7 +25,7 @@ export class MonitoringController {
 
   @UseGuards(TokenAuthGuard)
   @Get('prometheus')
-  getPrometheusStatus() {
+  getPrometheusStatus(): string {
     return '';
   }
 }
diff --git a/src/api/public/notes/notes.controller.ts b/src/api/public/notes/notes.controller.ts
index e7739529b..e641f17aa 100644
--- a/src/api/public/notes/notes.controller.ts
+++ b/src/api/public/notes/notes.controller.ts
@@ -15,7 +15,7 @@ import {
   Param,
   Post,
   Put,
-  Request,
+  Req,
   UnauthorizedException,
   UseGuards,
 } from '@nestjs/common';
@@ -41,6 +41,7 @@ import { RevisionMetadataDto } from '../../../revisions/revision-metadata.dto';
 import { RevisionDto } from '../../../revisions/revision.dto';
 import { PermissionsService } from '../../../permissions/permissions.service';
 import { Note } from '../../../notes/note.entity';
+import { Request } from 'express';
 
 @ApiTags('notes')
 @ApiSecurity('token')
@@ -59,7 +60,7 @@ export class NotesController {
   @UseGuards(TokenAuthGuard)
   @Post()
   async createNote(
-    @Request() req,
+    @Req() req: Request,
     @MarkdownBody() text: string,
   ): Promise<NoteDto> {
     // ToDo: provide user for createNoteDto
@@ -67,7 +68,7 @@ export class NotesController {
       throw new UnauthorizedException('Creating note denied!');
     }
     this.logger.debug('Got raw markdown:\n' + text);
-    return this.noteService.toNoteDto(
+    return await this.noteService.toNoteDto(
       await this.noteService.createNote(text, undefined, req.user),
     );
   }
@@ -75,7 +76,7 @@ export class NotesController {
   @UseGuards(TokenAuthGuard)
   @Get(':noteIdOrAlias')
   async getNote(
-    @Request() req,
+    @Req() req: Request,
     @Param('noteIdOrAlias') noteIdOrAlias: string,
   ): Promise<NoteDto> {
     let note: Note;
@@ -91,13 +92,13 @@ export class NotesController {
       throw new UnauthorizedException('Reading note denied!');
     }
     await this.historyService.createOrUpdateHistoryEntry(note, req.user);
-    return this.noteService.toNoteDto(note);
+    return await this.noteService.toNoteDto(note);
   }
 
   @UseGuards(TokenAuthGuard)
   @Post(':noteAlias')
   async createNamedNote(
-    @Request() req,
+    @Req() req: Request,
     @Param('noteAlias') noteAlias: string,
     @MarkdownBody() text: string,
   ): Promise<NoteDto> {
@@ -106,7 +107,7 @@ export class NotesController {
     }
     this.logger.debug('Got raw markdown:\n' + text, 'createNamedNote');
     try {
-      return this.noteService.toNoteDto(
+      return await this.noteService.toNoteDto(
         await this.noteService.createNote(text, noteAlias, req.user),
       );
     } catch (e) {
@@ -120,7 +121,7 @@ export class NotesController {
   @UseGuards(TokenAuthGuard)
   @Delete(':noteIdOrAlias')
   async deleteNote(
-    @Request() req,
+    @Req() req: Request,
     @Param('noteIdOrAlias') noteIdOrAlias: string,
   ): Promise<void> {
     try {
@@ -143,7 +144,7 @@ export class NotesController {
   @UseGuards(TokenAuthGuard)
   @Put(':noteIdOrAlias')
   async updateNote(
-    @Request() req,
+    @Req() req: Request,
     @Param('noteIdOrAlias') noteIdOrAlias: string,
     @MarkdownBody() text: string,
   ): Promise<NoteDto> {
@@ -153,7 +154,7 @@ export class NotesController {
         throw new UnauthorizedException('Updating note denied!');
       }
       this.logger.debug('Got raw markdown:\n' + text, 'updateNote');
-      return this.noteService.toNoteDto(
+      return await this.noteService.toNoteDto(
         await this.noteService.updateNote(note, text),
       );
     } catch (e) {
@@ -168,7 +169,7 @@ export class NotesController {
   @Get(':noteIdOrAlias/content')
   @Header('content-type', 'text/markdown')
   async getNoteContent(
-    @Request() req,
+    @Req() req: Request,
     @Param('noteIdOrAlias') noteIdOrAlias: string,
   ): Promise<string> {
     try {
@@ -188,7 +189,7 @@ export class NotesController {
   @UseGuards(TokenAuthGuard)
   @Get(':noteIdOrAlias/metadata')
   async getNoteMetadata(
-    @Request() req,
+    @Req() req: Request,
     @Param('noteIdOrAlias') noteIdOrAlias: string,
   ): Promise<NoteMetadataDto> {
     try {
@@ -196,7 +197,7 @@ export class NotesController {
       if (!this.permissionsService.mayRead(req.user, note)) {
         throw new UnauthorizedException('Reading note denied!');
       }
-      return this.noteService.toNoteMetadataDto(note);
+      return await this.noteService.toNoteMetadataDto(note);
     } catch (e) {
       if (e instanceof NotInDBError) {
         throw new NotFoundException(e.message);
@@ -211,7 +212,7 @@ export class NotesController {
   @UseGuards(TokenAuthGuard)
   @Put(':noteIdOrAlias/metadata/permissions')
   async updateNotePermissions(
-    @Request() req,
+    @Req() req: Request,
     @Param('noteIdOrAlias') noteIdOrAlias: string,
     @Body() updateDto: NotePermissionsUpdateDto,
   ): Promise<NotePermissionsDto> {
@@ -234,7 +235,7 @@ export class NotesController {
   @UseGuards(TokenAuthGuard)
   @Get(':noteIdOrAlias/revisions')
   async getNoteRevisions(
-    @Request() req,
+    @Req() req: Request,
     @Param('noteIdOrAlias') noteIdOrAlias: string,
   ): Promise<RevisionMetadataDto[]> {
     try {
@@ -243,7 +244,7 @@ export class NotesController {
         throw new UnauthorizedException('Reading note denied!');
       }
       const revisions = await this.revisionsService.getAllRevisions(note);
-      return Promise.all(
+      return await Promise.all(
         revisions.map((revision) =>
           this.revisionsService.toRevisionMetadataDto(revision),
         ),
@@ -259,7 +260,7 @@ export class NotesController {
   @UseGuards(TokenAuthGuard)
   @Get(':noteIdOrAlias/revisions/:revisionId')
   async getNoteRevision(
-    @Request() req,
+    @Req() req: Request,
     @Param('noteIdOrAlias') noteIdOrAlias: string,
     @Param('revisionId') revisionId: number,
   ): Promise<RevisionDto> {
diff --git a/src/api/utils/markdownbody-decorator.ts b/src/api/utils/markdownbody-decorator.ts
index 1c81df3ea..98dcf0836 100644
--- a/src/api/utils/markdownbody-decorator.ts
+++ b/src/api/utils/markdownbody-decorator.ts
@@ -18,6 +18,8 @@ import * as getRawBody from 'raw-body';
  *
  * Implementation inspired by https://stackoverflow.com/questions/52283713/how-do-i-pass-plain-text-as-my-request-body-using-nestjs
  */
+// Override naming convention as decorators are in PascalCase
+// eslint-disable-next-line @typescript-eslint/naming-convention
 export const MarkdownBody = createParamDecorator(
   async (_, context: ExecutionContext) => {
     // we have to check req.readable because of raw-body issue #57
@@ -39,7 +41,7 @@ export const MarkdownBody = createParamDecorator(
     }
   },
   [
-    (target, key) => {
+    (target, key): void => {
       ApiConsumes('text/markdown')(
         target,
         key,
diff --git a/src/auth/auth.service.spec.ts b/src/auth/auth.service.spec.ts
index 8506b5070..0aaa41ae3 100644
--- a/src/auth/auth.service.spec.ts
+++ b/src/auth/auth.service.spec.ts
@@ -4,6 +4,12 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/* eslint-disable
+@typescript-eslint/no-unsafe-call,
+@typescript-eslint/no-unsafe-member-access,
+@typescript-eslint/no-unsafe-return,
+@typescript-eslint/require-await */
+
 import { Test, TestingModule } from '@nestjs/testing';
 import { AuthService } from './auth.service';
 import { PassportModule } from '@nestjs/passport';
@@ -64,17 +70,17 @@ describe('AuthService', () => {
     it('works', async () => {
       const testPassword = 'thisIsATestPassword';
       const hash = await service.hashPassword(testPassword);
-      service
+      void service
         .checkPassword(testPassword, hash)
         .then((result) => expect(result).toBeTruthy());
     });
     it('fails, if secret is too short', async () => {
-      const secret = service.BufferToBase64Url(await service.randomString(54));
+      const secret = service.bufferToBase64Url(service.randomString(54));
       const hash = await service.hashPassword(secret);
-      service
+      void service
         .checkPassword(secret, hash)
         .then((result) => expect(result).toBeTruthy());
-      service
+      void service
         .checkPassword(secret.substr(0, secret.length - 1), hash)
         .then((result) => expect(result).toBeFalsy());
     });
@@ -194,12 +200,12 @@ describe('AuthService', () => {
     });
     describe('fails:', () => {
       it('the secret is missing', () => {
-        expect(
+        void expect(
           service.validateToken(`${authToken.keyId}`),
         ).rejects.toBeInstanceOf(TokenNotValidError);
       });
       it('the secret is too long', () => {
-        expect(
+        void expect(
           service.validateToken(`${authToken.keyId}.${'a'.repeat(73)}`),
         ).rejects.toBeInstanceOf(TokenNotValidError);
       });
@@ -277,10 +283,10 @@ describe('AuthService', () => {
     });
   });
 
-  describe('BufferToBase64Url', () => {
+  describe('bufferToBase64Url', () => {
     it('works', () => {
       expect(
-        service.BufferToBase64Url(
+        service.bufferToBase64Url(
           Buffer.from('testsentence is a test sentence'),
         ),
       ).toEqual('dGVzdHNlbnRlbmNlIGlzIGEgdGVzdCBzZW50ZW5jZQ');
@@ -293,7 +299,7 @@ describe('AuthService', () => {
       authToken.keyId = 'testKeyId';
       authToken.label = 'testLabel';
       authToken.createdAt = new Date();
-      const tokenDto = await service.toAuthTokenDto(authToken);
+      const tokenDto = service.toAuthTokenDto(authToken);
       expect(tokenDto.keyId).toEqual(authToken.keyId);
       expect(tokenDto.lastUsed).toBeNull();
       expect(tokenDto.label).toEqual(authToken.label);
diff --git a/src/auth/auth.service.ts b/src/auth/auth.service.ts
index 25aaaec12..833c24232 100644
--- a/src/auth/auth.service.ts
+++ b/src/auth/auth.service.ts
@@ -49,27 +49,27 @@ export class AuthService {
     }
     const accessToken = await this.getAuthTokenAndValidate(keyId, secret);
     await this.setLastUsedToken(keyId);
-    return this.usersService.getUserByUsername(accessToken.user.userName);
+    return await this.usersService.getUserByUsername(accessToken.user.userName);
   }
 
   async hashPassword(cleartext: string): Promise<string> {
     // hash the password with bcrypt and 2^12 iterations
     // this was decided on the basis of https://cheatsheetseries.owasp.org/cheatsheets/Password_Storage_Cheat_Sheet.html#bcrypt
-    return hash(cleartext, 12);
+    return await hash(cleartext, 12);
   }
 
   async checkPassword(cleartext: string, password: string): Promise<boolean> {
-    return compare(cleartext, password);
+    return await compare(cleartext, password);
   }
 
-  async randomString(length: number): Promise<Buffer> {
+  randomString(length: number): Buffer {
     if (length <= 0) {
       return null;
     }
     return randomBytes(length);
   }
 
-  BufferToBase64Url(text: Buffer): string {
+  bufferToBase64Url(text: Buffer): string {
     // This is necessary as the is no base64url encoding in the toString method
     // but as can be seen on https://tools.ietf.org/html/rfc4648#page-7
     // base64url is quite easy buildable from base64
@@ -93,8 +93,8 @@ export class AuthService {
         `User '${user.userName}' has already 200 tokens and can't have anymore`,
       );
     }
-    const secret = this.BufferToBase64Url(await this.randomString(54));
-    const keyId = this.BufferToBase64Url(await this.randomString(8));
+    const secret = this.bufferToBase64Url(this.randomString(54));
+    const keyId = this.bufferToBase64Url(this.randomString(8));
     const accessToken = await this.hashPassword(secret);
     let token;
     // Tokens can only be valid for a maximum of 2 years
@@ -117,11 +117,13 @@ export class AuthService {
         new Date(validUntil),
       );
     }
-    const createdToken = await this.authTokenRepository.save(token);
+    const createdToken = (await this.authTokenRepository.save(
+      token,
+    )) as AuthToken;
     return this.toAuthTokenWithSecretDto(createdToken, `${keyId}.${secret}`);
   }
 
-  async setLastUsedToken(keyId: string) {
+  async setLastUsedToken(keyId: string): Promise<void> {
     const accessToken = await this.authTokenRepository.findOne({
       where: { keyId: keyId },
     });
@@ -150,7 +152,7 @@ export class AuthService {
     ) {
       // tokens validUntil Date lies in the past
       throw new TokenNotValidError(
-        `AuthToken '${token}' is not valid since ${accessToken.validUntil}.`,
+        `AuthToken '${token}' is not valid since ${accessToken.validUntil.toISOString()}.`,
       );
     }
     return accessToken;
@@ -164,7 +166,7 @@ export class AuthService {
     return user.authTokens;
   }
 
-  async removeToken(keyId: string) {
+  async removeToken(keyId: string): Promise<void> {
     const token = await this.authTokenRepository.findOne({
       where: { keyId: keyId },
     });
@@ -173,7 +175,10 @@ export class AuthService {
 
   toAuthTokenDto(authToken: AuthToken): AuthTokenDto | null {
     if (!authToken) {
-      this.logger.warn(`Recieved ${authToken} argument!`, 'toAuthTokenDto');
+      this.logger.warn(
+        `Recieved ${String(authToken)} argument!`,
+        'toAuthTokenDto',
+      );
       return null;
     }
     const tokenDto: AuthTokenDto = {
@@ -208,17 +213,17 @@ export class AuthService {
 
   // Delete all non valid tokens  every sunday on 3:00 AM
   @Cron('0 0 3 * * 0')
-  async handleCron() {
-    return this.removeInvalidTokens();
+  async handleCron(): Promise<void> {
+    return await this.removeInvalidTokens();
   }
 
   // Delete all non valid tokens 5 sec after startup
   @Timeout(5000)
-  async handleTimeout() {
-    return this.removeInvalidTokens();
+  async handleTimeout(): Promise<void> {
+    return await this.removeInvalidTokens();
   }
 
-  async removeInvalidTokens() {
+  async removeInvalidTokens(): Promise<void> {
     const currentTime = new Date().getTime();
     const tokens: AuthToken[] = await this.authTokenRepository.find();
     let removedTokens = 0;
diff --git a/src/auth/mock-auth.guard.ts b/src/auth/mock-auth.guard.ts
index 5f1e40c6b..3b77dc9d6 100644
--- a/src/auth/mock-auth.guard.ts
+++ b/src/auth/mock-auth.guard.ts
@@ -7,14 +7,15 @@
 import { ExecutionContext, Injectable } from '@nestjs/common';
 import { UsersService } from '../users/users.service';
 import { User } from '../users/user.entity';
+import { Request } from 'express';
 
 @Injectable()
 export class MockAuthGuard {
   private user: User;
   constructor(private usersService: UsersService) {}
 
-  async canActivate(context: ExecutionContext) {
-    const req = context.switchToHttp().getRequest();
+  async canActivate(context: ExecutionContext): Promise<boolean> {
+    const req: Request = context.switchToHttp().getRequest();
     if (!this.user) {
       // this assures that we can create the user 'hardcoded', if we need them before any calls are made or
       // create them on the fly when the first call to the api is made
diff --git a/src/config/app.config.ts b/src/config/app.config.ts
index 69573ecc2..85b52d70b 100644
--- a/src/config/app.config.ts
+++ b/src/config/app.config.ts
@@ -25,7 +25,7 @@ const schema = Joi.object({
     .label('HD_LOGLEVEL'),
 });
 
-export default registerAs('appConfig', async () => {
+export default registerAs('appConfig', () => {
   const appConfig = schema.validate(
     {
       domain: process.env.HD_DOMAIN,
@@ -38,10 +38,10 @@ export default registerAs('appConfig', async () => {
     },
   );
   if (appConfig.error) {
-    const errorMessages = await appConfig.error.details.map(
+    const errorMessages = appConfig.error.details.map(
       (detail) => detail.message,
     );
     throw new Error(buildErrorMessage(errorMessages));
   }
-  return appConfig.value;
+  return appConfig.value as AppConfig;
 });
diff --git a/src/config/auth.config.ts b/src/config/auth.config.ts
index 1d7ce0269..8cc4132e7 100644
--- a/src/config/auth.config.ts
+++ b/src/config/auth.config.ts
@@ -227,7 +227,7 @@ const authSchema = Joi.object({
     .optional(),
 });
 
-export default registerAs('authConfig', async () => {
+export default registerAs('authConfig', () => {
   // ToDo: Validate these with Joi to prevent duplicate entries?
   const gitlabNames = toArrayConfig(
     process.env.HD_AUTH_GITLABS,
@@ -367,7 +367,7 @@ export default registerAs('authConfig', async () => {
     },
   );
   if (authConfig.error) {
-    const errorMessages = await authConfig.error.details
+    const errorMessages = authConfig.error.details
       .map((detail) => detail.message)
       .map((error) => {
         error = replaceAuthErrorsWithEnvironmentVariables(
@@ -398,5 +398,5 @@ export default registerAs('authConfig', async () => {
       });
     throw new Error(buildErrorMessage(errorMessages));
   }
-  return authConfig.value;
+  return authConfig.value as AuthConfig;
 });
diff --git a/src/config/csp.config.ts b/src/config/csp.config.ts
index 15da192c9..a3fe24fe8 100644
--- a/src/config/csp.config.ts
+++ b/src/config/csp.config.ts
@@ -18,7 +18,7 @@ const cspSchema = Joi.object({
   reportURI: Joi.string().optional().label('HD_CSP_REPORT_URI'),
 });
 
-export default registerAs('cspConfig', async () => {
+export default registerAs('cspConfig', () => {
   const cspConfig = cspSchema.validate(
     {
       enable: process.env.HD_CSP_ENABLE || true,
@@ -30,10 +30,10 @@ export default registerAs('cspConfig', async () => {
     },
   );
   if (cspConfig.error) {
-    const errorMessages = await cspConfig.error.details.map(
+    const errorMessages = cspConfig.error.details.map(
       (detail) => detail.message,
     );
     throw new Error(buildErrorMessage(errorMessages));
   }
-  return cspConfig.value;
+  return cspConfig.value as CspConfig;
 });
diff --git a/src/config/database.config.ts b/src/config/database.config.ts
index 652d74249..da437faf5 100644
--- a/src/config/database.config.ts
+++ b/src/config/database.config.ts
@@ -55,7 +55,7 @@ const databaseSchema = Joi.object({
     .label('HD_DATABASE_DIALECT'),
 });
 
-export default registerAs('databaseConfig', async () => {
+export default registerAs('databaseConfig', () => {
   const databaseConfig = databaseSchema.validate(
     {
       username: process.env.HD_DATABASE_USER,
@@ -72,10 +72,10 @@ export default registerAs('databaseConfig', async () => {
     },
   );
   if (databaseConfig.error) {
-    const errorMessages = await databaseConfig.error.details.map(
+    const errorMessages = databaseConfig.error.details.map(
       (detail) => detail.message,
     );
     throw new Error(buildErrorMessage(errorMessages));
   }
-  return databaseConfig.value;
+  return databaseConfig.value as DatabaseConfig;
 });
diff --git a/src/config/hsts.config.ts b/src/config/hsts.config.ts
index c64f3f416..0a1aa6916 100644
--- a/src/config/hsts.config.ts
+++ b/src/config/hsts.config.ts
@@ -28,7 +28,7 @@ const hstsSchema = Joi.object({
   preload: Joi.boolean().default(true).optional().label('HD_HSTS_PRELOAD'),
 });
 
-export default registerAs('hstsConfig', async () => {
+export default registerAs('hstsConfig', () => {
   const hstsConfig = hstsSchema.validate(
     {
       enable: process.env.HD_HSTS_ENABLE,
@@ -42,10 +42,10 @@ export default registerAs('hstsConfig', async () => {
     },
   );
   if (hstsConfig.error) {
-    const errorMessages = await hstsConfig.error.details.map(
+    const errorMessages = hstsConfig.error.details.map(
       (detail) => detail.message,
     );
     throw new Error(buildErrorMessage(errorMessages));
   }
-  return hstsConfig.value;
+  return hstsConfig.value as HstsConfig;
 });
diff --git a/src/config/media.config.ts b/src/config/media.config.ts
index 5f1d1e440..f06fc0791 100644
--- a/src/config/media.config.ts
+++ b/src/config/media.config.ts
@@ -75,7 +75,7 @@ const mediaSchema = Joi.object({
   },
 });
 
-export default registerAs('mediaConfig', async () => {
+export default registerAs('mediaConfig', () => {
   const mediaConfig = mediaSchema.validate(
     {
       backend: {
@@ -106,10 +106,10 @@ export default registerAs('mediaConfig', async () => {
     },
   );
   if (mediaConfig.error) {
-    const errorMessages = await mediaConfig.error.details.map(
+    const errorMessages = mediaConfig.error.details.map(
       (detail) => detail.message,
     );
     throw new Error(buildErrorMessage(errorMessages));
   }
-  return mediaConfig.value;
+  return mediaConfig.value as MediaConfig;
 });
diff --git a/src/config/utils.spec.ts b/src/config/utils.spec.ts
index c611c53cf..72d5196a5 100644
--- a/src/config/utils.spec.ts
+++ b/src/config/utils.spec.ts
@@ -4,6 +4,12 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/* eslint-disable
+@typescript-eslint/no-unsafe-call,
+@typescript-eslint/no-unsafe-member-access,
+@typescript-eslint/no-unsafe-return,
+@typescript-eslint/require-await */
+
 import {
   replaceAuthErrorsWithEnvironmentVariables,
   toArrayConfig,
diff --git a/src/config/utils.ts b/src/config/utils.ts
index 041d91301..50a695f6e 100644
--- a/src/config/utils.ts
+++ b/src/config/utils.ts
@@ -4,19 +4,17 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-export const toArrayConfig = (configValue: string, separator = ',') => {
+export function toArrayConfig(configValue: string, separator = ','): string[] {
   if (!configValue) {
     return [];
   }
-
   if (!configValue.includes(separator)) {
     return [configValue.trim()];
   }
-
   return configValue.split(separator).map((arrayItem) => arrayItem.trim());
-};
+}
 
-export const buildErrorMessage = (errorMessages: string[]): string => {
+export function buildErrorMessage(errorMessages: string[]): string {
   let totalErrorMessage = 'There were some errors with your configuration:';
   for (const message of errorMessages) {
     totalErrorMessage += '\n - ';
@@ -25,19 +23,19 @@ export const buildErrorMessage = (errorMessages: string[]): string => {
   totalErrorMessage +=
     '\nFor further information, have a look at our configuration docs at https://docs.hedgedoc.org/configuration';
   return totalErrorMessage;
-};
+}
 
-export const replaceAuthErrorsWithEnvironmentVariables = (
+export function replaceAuthErrorsWithEnvironmentVariables(
   message: string,
   name: string,
   replacement: string,
   arrayOfNames: string[],
-): string => {
+): string {
   // this builds a regex like /"gitlab\[(\d+)]\./ to extract the position in the arrayOfNames
   const regex = new RegExp('"' + name + '\\[(\\d+)]\\.', 'g');
   message = message.replace(
     regex,
-    (_, index) => `"${replacement}${arrayOfNames[index]}.`,
+    (_, index: number) => `"${replacement}${arrayOfNames[index]}.`,
   );
   message = message.replace('.providerName', '_PROVIDER_NAME');
   message = message.replace('.baseURL', '_BASE_URL');
@@ -88,4 +86,4 @@ export const replaceAuthErrorsWithEnvironmentVariables = (
   message = message.replace('.rolesClaim', '_ROLES_CLAIM');
   message = message.replace('.accessRole', '_ACCESS_ROLE');
   return message;
-};
+}
diff --git a/src/groups/groups.service.spec.ts b/src/groups/groups.service.spec.ts
index 827d2d1f0..840fd2029 100644
--- a/src/groups/groups.service.spec.ts
+++ b/src/groups/groups.service.spec.ts
@@ -31,7 +31,7 @@ describe('GroupsService', () => {
 
     service = module.get<GroupsService>(GroupsService);
     groupRepo = module.get<Repository<Group>>(getRepositoryToken(Group));
-    group = Group.create('testGroup', 'Superheros') as Group;
+    group = Group.create('testGroup', 'Superheros');
   });
 
   it('should be defined', () => {
diff --git a/src/groups/groups.service.ts b/src/groups/groups.service.ts
index 042ef0996..ea2e7fd0d 100644
--- a/src/groups/groups.service.ts
+++ b/src/groups/groups.service.ts
@@ -45,7 +45,7 @@ export class GroupsService {
    */
   toGroupDto(group: Group | null | undefined): GroupInfoDto | null {
     if (!group) {
-      this.logger.warn(`Recieved ${group} argument!`, 'toGroupDto');
+      this.logger.warn(`Recieved ${String(group)} argument!`, 'toGroupDto');
       return null;
     }
     return {
diff --git a/src/history/history.service.spec.ts b/src/history/history.service.spec.ts
index af4613dc1..fe104eb1c 100644
--- a/src/history/history.service.spec.ts
+++ b/src/history/history.service.spec.ts
@@ -4,6 +4,12 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/* eslint-disable
+@typescript-eslint/no-unsafe-call,
+@typescript-eslint/no-unsafe-member-access,
+@typescript-eslint/no-unsafe-return,
+@typescript-eslint/require-await */
+
 import { Test, TestingModule } from '@nestjs/testing';
 import { LoggerModule } from '../logger/logger.module';
 import { HistoryService } from './history.service';
@@ -248,7 +254,7 @@ describe('HistoryService', () => {
         const historyEntry = HistoryEntry.create(user, note);
         historyEntry.pinStatus = true;
         jest.spyOn(noteRepo, 'findOne').mockResolvedValueOnce(note);
-        const historyEntryDto = await service.toHistoryEntryDto(historyEntry);
+        const historyEntryDto = service.toHistoryEntryDto(historyEntry);
         expect(historyEntryDto.pinStatus).toEqual(true);
         expect(historyEntryDto.identifier).toEqual(alias);
         expect(historyEntryDto.tags).toEqual(tags);
@@ -271,7 +277,7 @@ describe('HistoryService', () => {
         const historyEntry = HistoryEntry.create(user, note);
         historyEntry.pinStatus = true;
         jest.spyOn(noteRepo, 'findOne').mockResolvedValueOnce(note);
-        const historyEntryDto = await service.toHistoryEntryDto(historyEntry);
+        const historyEntryDto = service.toHistoryEntryDto(historyEntry);
         expect(historyEntryDto.pinStatus).toEqual(true);
         expect(historyEntryDto.identifier).toEqual(id);
         expect(historyEntryDto.tags).toEqual(tags);
diff --git a/src/history/history.service.ts b/src/history/history.service.ts
index 84583220e..aef7bc389 100644
--- a/src/history/history.service.ts
+++ b/src/history/history.service.ts
@@ -79,7 +79,7 @@ export class HistoryService {
       );
     }
     entry.pinStatus = updateDto.pinStatus;
-    return this.historyEntryRepository.save(entry);
+    return await this.historyEntryRepository.save(entry);
   }
 
   async deleteHistoryEntry(noteIdOrAlias: string, user: User): Promise<void> {
@@ -93,7 +93,7 @@ export class HistoryService {
     return;
   }
 
-  async toHistoryEntryDto(entry: HistoryEntry): Promise<HistoryEntryDto> {
+  toHistoryEntryDto(entry: HistoryEntry): HistoryEntryDto {
     return {
       identifier: entry.note.alias ? entry.note.alias : entry.note.id,
       lastVisited: entry.updatedAt,
diff --git a/src/logger/console-logger.service.ts b/src/logger/console-logger.service.ts
index f280e6859..aeb1af10b 100644
--- a/src/logger/console-logger.service.ts
+++ b/src/logger/console-logger.service.ts
@@ -6,23 +6,23 @@
 
 import { Injectable, Optional, Scope } from '@nestjs/common';
 import { isObject } from '@nestjs/common/utils/shared.utils';
-import * as clc from 'cli-color';
+import clc = require('cli-color');
 import DateTimeFormatOptions = Intl.DateTimeFormatOptions;
 
 @Injectable({ scope: Scope.TRANSIENT })
 export class ConsoleLoggerService {
-  private classContext;
+  private classContext: string;
   private lastTimestamp: number;
 
   constructor(@Optional() context?: string) {
     this.classContext = context;
   }
 
-  setContext(context: string) {
+  setContext(context: string): void {
     this.classContext = context;
   }
 
-  error(message: any, trace = '', functionContext?: string) {
+  error(message: unknown, trace = '', functionContext?: string): void {
     this.printMessage(
       message,
       clc.red,
@@ -32,7 +32,7 @@ export class ConsoleLoggerService {
     this.printStackTrace(trace);
   }
 
-  log(message: any, functionContext?: string) {
+  log(message: unknown, functionContext?: string): void {
     this.printMessage(
       message,
       clc.green,
@@ -41,7 +41,7 @@ export class ConsoleLoggerService {
     );
   }
 
-  warn(message: any, functionContext?: string) {
+  warn(message: unknown, functionContext?: string): void {
     this.printMessage(
       message,
       clc.yellow,
@@ -50,7 +50,7 @@ export class ConsoleLoggerService {
     );
   }
 
-  debug(message: any, functionContext?: string) {
+  debug(message: unknown, functionContext?: string): void {
     this.printMessage(
       message,
       clc.magentaBright,
@@ -59,7 +59,7 @@ export class ConsoleLoggerService {
     );
   }
 
-  verbose(message: any, functionContext?: string) {
+  verbose(message: unknown, functionContext?: string): void {
     this.printMessage(
       message,
       clc.cyanBright,
@@ -68,7 +68,7 @@ export class ConsoleLoggerService {
     );
   }
 
-  private makeContextString(functionContext) {
+  private makeContextString(functionContext: string): string {
     let context = this.classContext;
     if (functionContext) {
       context += '.' + functionContext + '()';
@@ -77,14 +77,14 @@ export class ConsoleLoggerService {
   }
 
   private printMessage(
-    message: any,
+    message: unknown,
     color: (message: string) => string,
     context = '',
     isTimeDiffEnabled?: boolean,
-  ) {
+  ): void {
     const output = isObject(message)
       ? `${color('Object:')}\n${JSON.stringify(message, null, 2)}\n`
-      : color(message);
+      : color(message as string);
 
     const localeStringOptions: DateTimeFormatOptions = {
       year: 'numeric',
@@ -117,7 +117,7 @@ export class ConsoleLoggerService {
     return result;
   }
 
-  private printStackTrace(trace: string) {
+  private printStackTrace(trace: string): void {
     if (!trace) {
       return;
     }
diff --git a/src/logger/nest-console-logger.service.ts b/src/logger/nest-console-logger.service.ts
index c31af1ef7..2fe5b62a4 100644
--- a/src/logger/nest-console-logger.service.ts
+++ b/src/logger/nest-console-logger.service.ts
@@ -12,27 +12,27 @@ Injectable();
 export class NestConsoleLoggerService implements LoggerService {
   private consoleLoggerService = new ConsoleLoggerService();
 
-  debug(message: any, context?: string): any {
+  debug(message: unknown, context?: string): void {
     this.consoleLoggerService.setContext(context);
     this.consoleLoggerService.debug(message);
   }
 
-  error(message: any, trace?: string, context?: string): any {
+  error(message: unknown, trace?: string, context?: string): void {
     this.consoleLoggerService.setContext(context);
     this.consoleLoggerService.error(message, trace);
   }
 
-  log(message: any, context?: string): any {
+  log(message: unknown, context?: string): void {
     this.consoleLoggerService.setContext(context);
     this.consoleLoggerService.log(message);
   }
 
-  verbose(message: any, context?: string): any {
+  verbose(message: unknown, context?: string): void {
     this.consoleLoggerService.setContext(context);
     this.consoleLoggerService.verbose(message);
   }
 
-  warn(message: any, context?: string): any {
+  warn(message: unknown, context?: string): void {
     this.consoleLoggerService.setContext(context);
     this.consoleLoggerService.warn(message);
   }
diff --git a/src/main.ts b/src/main.ts
index 36a4f596d..e9c2bb5cd 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -15,7 +15,7 @@ import { NestConsoleLoggerService } from './logger/nest-console-logger.service';
 import { setupPrivateApiDocs, setupPublicApiDocs } from './utils/swagger';
 import { BackendType } from './media/backends/backend-type.enum';
 
-async function bootstrap() {
+async function bootstrap(): Promise<void> {
   const app = await NestFactory.create<NestExpressApplication>(AppModule);
   const logger = await app.resolve(NestConsoleLoggerService);
   logger.log('Switching logger', 'AppBootstrap');
@@ -49,4 +49,4 @@ async function bootstrap() {
   logger.log(`Listening on port ${appConfig.port}`, 'AppBootstrap');
 }
 
-bootstrap();
+void bootstrap();
diff --git a/src/media/backends/filesystem-backend.ts b/src/media/backends/filesystem-backend.ts
index cefc088c3..cf9ce7cce 100644
--- a/src/media/backends/filesystem-backend.ts
+++ b/src/media/backends/filesystem-backend.ts
@@ -38,7 +38,7 @@ export class FilesystemBackend implements MediaBackend {
       await fs.writeFile(filePath, buffer, null);
       return ['/' + filePath, null];
     } catch (e) {
-      this.logger.error(e.message, e.stack, 'saveFile');
+      this.logger.error((e as Error).message, (e as Error).stack, 'saveFile');
       throw new MediaBackendError(`Could not save '${filePath}'`);
     }
   }
@@ -46,9 +46,9 @@ export class FilesystemBackend implements MediaBackend {
   async deleteFile(fileName: string, _: BackendData): Promise<void> {
     const filePath = this.getFilePath(fileName);
     try {
-      return fs.unlink(filePath);
+      return await fs.unlink(filePath);
     } catch (e) {
-      this.logger.error(e.message, e.stack, 'deleteFile');
+      this.logger.error((e as Error).message, (e as Error).stack, 'deleteFile');
       throw new MediaBackendError(`Could not delete '${filePath}'`);
     }
   }
@@ -57,7 +57,7 @@ export class FilesystemBackend implements MediaBackend {
     return join(this.uploadDirectory, fileName);
   }
 
-  private async ensureDirectory() {
+  private async ensureDirectory(): Promise<void> {
     try {
       await fs.access(this.uploadDirectory);
     } catch (e) {
@@ -67,7 +67,11 @@ export class FilesystemBackend implements MediaBackend {
         );
         await fs.mkdir(this.uploadDirectory);
       } catch (e) {
-        this.logger.error(e.message, e.stack, 'deleteFile');
+        this.logger.error(
+          (e as Error).message,
+          (e as Error).stack,
+          'deleteFile',
+        );
         throw new MediaBackendError(
           `Could not create '${this.uploadDirectory}'`,
         );
diff --git a/src/media/media.service.spec.ts b/src/media/media.service.spec.ts
index 8773be3da..d84a98dba 100644
--- a/src/media/media.service.spec.ts
+++ b/src/media/media.service.spec.ts
@@ -4,6 +4,12 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/* eslint-disable
+@typescript-eslint/no-unsafe-call,
+@typescript-eslint/no-unsafe-member-access,
+@typescript-eslint/no-unsafe-return,
+@typescript-eslint/require-await */
+
 import { ConfigModule } from '@nestjs/config';
 import { Test, TestingModule } from '@nestjs/testing';
 import { getRepositoryToken } from '@nestjs/typeorm';
@@ -96,7 +102,7 @@ describe('MediaService', () => {
   });
 
   describe('saveFile', () => {
-    beforeEach(async () => {
+    beforeEach(() => {
       const user = User.create('hardcoded', 'Testy') as User;
       const alias = 'alias';
       const note = Note.create(user, alias);
diff --git a/src/monitoring/monitoring.service.ts b/src/monitoring/monitoring.service.ts
index 92ef6452d..260c57312 100644
--- a/src/monitoring/monitoring.service.ts
+++ b/src/monitoring/monitoring.service.ts
@@ -5,23 +5,20 @@
  */
 
 import { Injectable } from '@nestjs/common';
-import { ServerStatusDto } from './server-status.dto';
 import { promises as fs } from 'fs';
 import { join as joinPath } from 'path';
+import { ServerStatusDto, ServerVersion } from './server-status.dto';
 
-let versionCache: null | {
-  major: number;
-  minor: number;
-  patch: number;
-  preRelease?: string;
-  commit?: string;
-} = null;
-async function getServerVersionFromPackageJson() {
+let versionCache: ServerVersion;
+
+async function getServerVersionFromPackageJson(): Promise<ServerVersion> {
   if (versionCache === null) {
     const rawFileContent: string = await fs.readFile(
       joinPath(__dirname, '../../package.json'),
       { encoding: 'utf8' },
     );
+    // TODO: Should this be validated in more detail?
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
     const packageInfo: { version: string } = JSON.parse(rawFileContent);
     const versionParts: number[] = packageInfo.version
       .split('.')
diff --git a/src/monitoring/server-status.dto.ts b/src/monitoring/server-status.dto.ts
index ac7f7407d..8bea15f1e 100644
--- a/src/monitoring/server-status.dto.ts
+++ b/src/monitoring/server-status.dto.ts
@@ -4,14 +4,16 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+export interface ServerVersion {
+  major: number;
+  minor: number;
+  patch: number;
+  preRelease?: string;
+  commit?: string;
+}
+
 export class ServerStatusDto {
-  serverVersion: {
-    major: number;
-    minor: number;
-    patch: number;
-    preRelease?: string;
-    commit?: string;
-  };
+  serverVersion: ServerVersion;
   onlineNotes: number;
   onlineUsers: number;
   destictOnlineUsers: number;
diff --git a/src/notes/note.entity.ts b/src/notes/note.entity.ts
index dd1dba79d..1adcef9cb 100644
--- a/src/notes/note.entity.ts
+++ b/src/notes/note.entity.ts
@@ -85,7 +85,7 @@ export class Note {
     newNote.authorColors = [];
     newNote.userPermissions = [];
     newNote.groupPermissions = [];
-    newNote.revisions = Promise.resolve([]);
+    newNote.revisions = Promise.resolve([]) as Promise<Revision[]>;
     newNote.description = null;
     newNote.title = null;
     newNote.tags = [];
diff --git a/src/notes/notes.service.spec.ts b/src/notes/notes.service.spec.ts
index 18a02dba5..f1858f30b 100644
--- a/src/notes/notes.service.spec.ts
+++ b/src/notes/notes.service.spec.ts
@@ -4,6 +4,12 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/* eslint-disable @typescript-eslint/require-await */
+/* eslint-disable
+@typescript-eslint/no-unsafe-assignment,
+@typescript-eslint/no-unsafe-member-access
+*/
+
 import { Test, TestingModule } from '@nestjs/testing';
 import { getRepositoryToken } from '@nestjs/typeorm';
 import { LoggerModule } from '../logger/logger.module';
@@ -189,7 +195,7 @@ describe('NotesService', () => {
       const newNote = await service.createNote(content);
       const revisions = await newNote.revisions;
       jest.spyOn(revisionRepo, 'findOne').mockResolvedValueOnce(revisions[0]);
-      service.getNoteContent(newNote).then((result) => {
+      void service.getNoteContent(newNote).then((result) => {
         expect(result).toEqual(content);
       });
     });
@@ -204,7 +210,7 @@ describe('NotesService', () => {
       const newNote = await service.createNote(content);
       const revisions = await newNote.revisions;
       jest.spyOn(revisionRepo, 'findOne').mockResolvedValueOnce(revisions[0]);
-      service.getLatestRevision(newNote).then((result) => {
+      void service.getLatestRevision(newNote).then((result) => {
         expect(result).toEqual(revisions[0]);
       });
     });
@@ -221,7 +227,7 @@ describe('NotesService', () => {
       const newNote = await service.createNote(content);
       const revisions = await newNote.revisions;
       jest.spyOn(revisionRepo, 'findOne').mockResolvedValueOnce(revisions[0]);
-      service.getLatestRevision(newNote).then((result) => {
+      void service.getLatestRevision(newNote).then((result) => {
         expect(result).toEqual(revisions[0]);
       });
     });
@@ -594,7 +600,7 @@ describe('NotesService', () => {
   describe('toNotePermissionsDto', () => {
     it('works', async () => {
       const user = User.create('hardcoded', 'Testy') as User;
-      const group = Group.create('testGroup', 'testGroup') as Group;
+      const group = Group.create('testGroup', 'testGroup');
       const note = Note.create(user);
       note.userPermissions = [
         {
@@ -610,7 +616,7 @@ describe('NotesService', () => {
           canEdit: true,
         },
       ];
-      const permissions = await service.toNotePermissionsDto(note);
+      const permissions = service.toNotePermissionsDto(note);
       expect(permissions.owner.userName).toEqual(user.userName);
       expect(permissions.sharedToUsers).toHaveLength(1);
       expect(permissions.sharedToUsers[0].user.userName).toEqual(user.userName);
@@ -627,7 +633,7 @@ describe('NotesService', () => {
     it('works', async () => {
       const user = User.create('hardcoded', 'Testy') as User;
       const otherUser = User.create('other hardcoded', 'Testy2') as User;
-      const group = Group.create('testGroup', 'testGroup') as Group;
+      const group = Group.create('testGroup', 'testGroup');
       const content = 'testContent';
       jest
         .spyOn(noteRepo, 'save')
@@ -718,7 +724,7 @@ describe('NotesService', () => {
       const user = User.create('hardcoded', 'Testy') as User;
       const otherUser = User.create('other hardcoded', 'Testy2') as User;
       otherUser.userName = 'other hardcoded user';
-      const group = Group.create('testGroup', 'testGroup') as Group;
+      const group = Group.create('testGroup', 'testGroup');
       const content = 'testContent';
       jest
         .spyOn(noteRepo, 'save')
diff --git a/src/notes/notes.service.ts b/src/notes/notes.service.ts
index 5b99e6f78..0ff2e7112 100644
--- a/src/notes/notes.service.ts
+++ b/src/notes/notes.service.ts
@@ -202,7 +202,7 @@ export class NotesService {
     //TODO: Calculate patch
     revisions.push(Revision.create(noteContent, noteContent));
     note.revisions = Promise.resolve(revisions);
-    return this.noteRepository.save(note);
+    return await this.noteRepository.save(note);
   }
 
   /**
@@ -295,12 +295,11 @@ export class NotesService {
   }
 
   /**
-   * @async
    * Build NotePermissionsDto from a note.
    * @param {Note} note - the note to use
    * @return {NotePermissionsDto} the built NotePermissionDto
    */
-  async toNotePermissionsDto(note: Note): Promise<NotePermissionsDto> {
+  toNotePermissionsDto(note: Note): NotePermissionsDto {
     return {
       owner: this.usersService.toUserDto(note.owner),
       sharedToUsers: note.userPermissions.map((noteUserPermission) => ({
@@ -331,7 +330,7 @@ export class NotesService {
       editedBy: note.authorColors.map(
         (authorColor) => authorColor.user.userName,
       ),
-      permissions: await this.toNotePermissionsDto(note),
+      permissions: this.toNotePermissionsDto(note),
       tags: this.toTagList(note),
       updateTime: (await this.getLatestRevision(note)).createdAt,
       updateUser: this.usersService.toUserDto(
diff --git a/src/permissions/permissions.service.spec.ts b/src/permissions/permissions.service.spec.ts
index 6396eb09c..a5bcde491 100644
--- a/src/permissions/permissions.service.spec.ts
+++ b/src/permissions/permissions.service.spec.ts
@@ -4,24 +4,30 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/* eslint-disable
+@typescript-eslint/no-unsafe-call,
+@typescript-eslint/no-unsafe-member-access,
+@typescript-eslint/no-unsafe-return,
+@typescript-eslint/require-await */
+
 import { Test, TestingModule } from '@nestjs/testing';
-import { LoggerModule } from '../logger/logger.module';
-import { GuestPermission, PermissionsService } from './permissions.service';
-import { User } from '../users/user.entity';
-import { Note } from '../notes/note.entity';
-import { UsersModule } from '../users/users.module';
-import { NotesModule } from '../notes/notes.module';
-import { PermissionsModule } from './permissions.module';
 import { getRepositoryToken } from '@nestjs/typeorm';
+import { AuthToken } from '../auth/auth-token.entity';
+import { Group } from '../groups/group.entity';
+import { LoggerModule } from '../logger/logger.module';
+import { AuthorColor } from '../notes/author-color.entity';
+import { Note } from '../notes/note.entity';
+import { NotesModule } from '../notes/notes.module';
+import { Tag } from '../notes/tag.entity';
+import { Authorship } from '../revisions/authorship.entity';
+import { Revision } from '../revisions/revision.entity';
+import { Identity } from '../users/identity.entity';
+import { User } from '../users/user.entity';
+import { UsersModule } from '../users/users.module';
 import { NoteGroupPermission } from './note-group-permission.entity';
 import { NoteUserPermission } from './note-user-permission.entity';
-import { Identity } from '../users/identity.entity';
-import { AuthToken } from '../auth/auth-token.entity';
-import { Authorship } from '../revisions/authorship.entity';
-import { AuthorColor } from '../notes/author-color.entity';
-import { Revision } from '../revisions/revision.entity';
-import { Tag } from '../notes/tag.entity';
-import { Group } from '../groups/group.entity';
+import { PermissionsModule } from './permissions.module';
+import { GuestPermission, PermissionsService } from './permissions.service';
 
 describe('PermissionsService', () => {
   let permissionsService: PermissionsService;
@@ -148,6 +154,7 @@ describe('PermissionsService', () => {
       noteEverybodyWrite,
     ];
   }
+
   const notes = createNoteUserPermissionNotes();
 
   describe('mayRead works with', () => {
@@ -336,6 +343,7 @@ describe('PermissionsService', () => {
       [user2groupWrite, user2groupRead, null], // group4: don't allow user1 to read or write via group
     ];
   }
+
   /*
    * creates the matrix multiplication of group0 to group4 of createAllNoteGroupPermissions
    */
@@ -350,7 +358,7 @@ describe('PermissionsService', () => {
         for (const group2 of noteGroupPermissions[2]) {
           for (const group3 of noteGroupPermissions[3]) {
             for (const group4 of noteGroupPermissions[4]) {
-              const insert = [];
+              const insert: NoteGroupPermission[] = [];
               let readPermission = false;
               let writePermission = false;
               if (group0 !== null) {
@@ -408,7 +416,10 @@ describe('PermissionsService', () => {
   ): NoteGroupPermission[][] {
     const results = [];
 
-    function permute(arr, memo) {
+    function permute(
+      arr: NoteGroupPermission[],
+      memo: NoteGroupPermission[],
+    ): NoteGroupPermission[][] {
       let cur;
 
       for (let i = 0; i < arr.length; i++) {
@@ -456,15 +467,15 @@ describe('PermissionsService', () => {
       note.groupPermissions = permission.permissions;
       let permissionString = '';
       for (const perm of permission.permissions) {
-        permissionString += ' ' + perm.group.name + ':' + perm.canEdit;
+        permissionString += ` ${perm.group.name}:${String(perm.canEdit)}`;
       }
-      it('mayWrite - test #' + i + ':' + permissionString, () => {
+      it(`mayWrite - test #${i}:${permissionString}`, () => {
         permissionsService.guestPermission = guestPermission;
         expect(permissionsService.mayWrite(user1, note)).toEqual(
           permission.allowsWrite,
         );
       });
-      it('mayRead - test #' + i + ':' + permissionString, () => {
+      it(`mayRead - test #${i}:${permissionString}`, () => {
         permissionsService.guestPermission = guestPermission;
         expect(permissionsService.mayRead(user1, note)).toEqual(
           permission.allowsRead,
diff --git a/src/users/users.service.ts b/src/users/users.service.ts
index b29b0e30e..7714d0dd5 100644
--- a/src/users/users.service.ts
+++ b/src/users/users.service.ts
@@ -26,7 +26,7 @@ export class UsersService {
     return this.userRepository.save(user);
   }
 
-  async deleteUser(userName: string) {
+  async deleteUser(userName: string): Promise<void> {
     // TODO: Handle owned notes and edits
     const user = await this.userRepository.findOne({
       where: { userName: userName },
@@ -56,7 +56,7 @@ export class UsersService {
 
   toUserDto(user: User | null | undefined): UserInfoDto | null {
     if (!user) {
-      this.logger.warn(`Recieved ${user} argument!`, 'toUserDto');
+      this.logger.warn(`Recieved ${String(user)} argument!`, 'toUserDto');
       return null;
     }
     return {
diff --git a/src/utils/swagger.ts b/src/utils/swagger.ts
index f0167992c..e242d5397 100644
--- a/src/utils/swagger.ts
+++ b/src/utils/swagger.ts
@@ -9,7 +9,7 @@ import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
 import { PrivateApiModule } from '../api/private/private-api.module';
 import { PublicApiModule } from '../api/public/public-api.module';
 
-export function setupPublicApiDocs(app: INestApplication) {
+export function setupPublicApiDocs(app: INestApplication): void {
   const publicApiOptions = new DocumentBuilder()
     .setTitle('HedgeDoc Public API')
     // TODO: Use real version
@@ -25,7 +25,7 @@ export function setupPublicApiDocs(app: INestApplication) {
   SwaggerModule.setup('apidoc', app, publicApi);
 }
 
-export function setupPrivateApiDocs(app: INestApplication) {
+export function setupPrivateApiDocs(app: INestApplication): void {
   const privateApiOptions = new DocumentBuilder()
     .setTitle('HedgeDoc Private API')
     // TODO: Use real version
diff --git a/test/public-api/me.e2e-spec.ts b/test/public-api/me.e2e-spec.ts
index 42f73c940..aa4733080 100644
--- a/test/public-api/me.e2e-spec.ts
+++ b/test/public-api/me.e2e-spec.ts
@@ -4,6 +4,11 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/* eslint-disable
+@typescript-eslint/no-unsafe-assignment,
+@typescript-eslint/no-unsafe-member-access
+*/
+
 import { INestApplication } from '@nestjs/common';
 import { Test } from '@nestjs/testing';
 import * as request from 'supertest';
@@ -94,7 +99,7 @@ describe('Notes', () => {
       .expect(200);
     const history = <HistoryEntryDto[]>response.body;
     for (const historyEntry of history) {
-      if ((<HistoryEntryDto>historyEntry).identifier === 'testGetHistory') {
+      if (historyEntry.identifier === 'testGetHistory') {
         expect(historyEntry).toEqual(createdHistoryEntry);
       }
     }
@@ -116,7 +121,7 @@ describe('Notes', () => {
     historyEntry = null;
     for (const e of history) {
       if (e.note.alias === noteName) {
-        historyEntry = await historyService.toHistoryEntryDto(e);
+        historyEntry = historyService.toHistoryEntryDto(e);
       }
     }
     expect(historyEntry.pinStatus).toEqual(true);
@@ -133,7 +138,7 @@ describe('Notes', () => {
     const history = await historyService.getEntriesByUser(user);
     let historyEntry: HistoryEntry = null;
     for (const e of history) {
-      if ((<HistoryEntry>e).note.alias === noteName) {
+      if (e.note.alias === noteName) {
         historyEntry = e;
       }
     }
diff --git a/test/public-api/media.e2e-spec.ts b/test/public-api/media.e2e-spec.ts
index f2a1cf8bd..89843b1cf 100644
--- a/test/public-api/media.e2e-spec.ts
+++ b/test/public-api/media.e2e-spec.ts
@@ -4,6 +4,11 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/* eslint-disable
+@typescript-eslint/no-unsafe-assignment,
+@typescript-eslint/no-unsafe-member-access
+*/
+
 import { ConfigModule, ConfigService } from '@nestjs/config';
 import { NestExpressApplication } from '@nestjs/platform-express';
 import { Test } from '@nestjs/testing';
@@ -78,7 +83,7 @@ describe('Notes', () => {
       .set('HedgeDoc-Note', 'test_upload_media')
       .expect('Content-Type', /json/)
       .expect(201);
-    const path = uploadResponse.body.link;
+    const path: string = uploadResponse.body.link;
     const testImage = await fs.readFile('test/public-api/fixtures/test.png');
     const downloadResponse = await request(app.getHttpServer()).get(path);
     expect(downloadResponse.body).toEqual(testImage);
diff --git a/test/public-api/notes.e2e-spec.ts b/test/public-api/notes.e2e-spec.ts
index f201f3d67..4aaa18ef1 100644
--- a/test/public-api/notes.e2e-spec.ts
+++ b/test/public-api/notes.e2e-spec.ts
@@ -4,6 +4,11 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/* eslint-disable
+@typescript-eslint/no-unsafe-assignment,
+@typescript-eslint/no-unsafe-member-access
+*/
+
 import { INestApplication } from '@nestjs/common';
 import { ConfigModule } from '@nestjs/config';
 import { Test } from '@nestjs/testing';
@@ -149,7 +154,7 @@ describe('Notes', () => {
         .set('Content-Type', 'text/markdown')
         .send(changedContent)
         .expect(200);
-      await expect(
+      expect(
         await notesService.getNoteContent(
           await notesService.getNoteByIdOrAlias('test4'),
         ),
@@ -239,7 +244,7 @@ describe('Notes', () => {
       const note = await notesService.createNote(content, 'test7', user);
       const revision = await notesService.getLatestRevision(note);
       const response = await request(app.getHttpServer())
-        .get('/notes/test7/revisions/' + revision.id)
+        .get(`/notes/test7/revisions/${revision.id}`)
         .expect('Content-Type', /json/)
         .expect(200);
       expect(response.body.content).toEqual(content);
diff --git a/types/express/index.d.ts b/types/express/index.d.ts
new file mode 100644
index 000000000..13bbf4862
--- /dev/null
+++ b/types/express/index.d.ts
@@ -0,0 +1,13 @@
+/*
+ * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { User} from '../../src/users/user.entity';
+
+declare module 'express' {
+  export interface Request {
+    user?: User;
+  }
+}
diff --git a/yarn.lock b/yarn.lock
index 3e8f27d75..4374e2eb4 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -846,6 +846,11 @@
     "@types/connect" "*"
     "@types/node" "*"
 
+"@types/cli-color@^2.0.0":
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/@types/cli-color/-/cli-color-2.0.0.tgz#dc64e32da0fb9ea1814300fb468a58e833ce71a6"
+  integrity sha512-E2Oisr73FjwxMHkYU6RcN9P9mmrbG4TNQMIebWhazYxOgWRzA7s4hM+DtAs6ZwiwKFbPst42v1XUAC1APIhRJA==
+
 "@types/connect@*":
   version "3.4.34"
   resolved "https://registry.yarnpkg.com/@types/connect/-/connect-3.4.34.tgz#170a40223a6d666006d93ca128af2beb1d9b1901"
@@ -1095,6 +1100,11 @@
     "@types/mime" "^1"
     "@types/node" "*"
 
+"@types/shortid@^0.0.29":
+  version "0.0.29"
+  resolved "https://registry.yarnpkg.com/@types/shortid/-/shortid-0.0.29.tgz#8093ee0416a6e2bf2aa6338109114b3fbffa0e9b"
+  integrity sha1-gJPuBBam4r8qpjOBCRFLP7/6Dps=
+
 "@types/source-list-map@*":
   version "0.1.2"
   resolved "https://registry.yarnpkg.com/@types/source-list-map/-/source-list-map-0.1.2.tgz#0078836063ffaf17412349bba364087e0ac02ec9"