diff --git a/package.json b/package.json
index 4b6dd5c77..1bfd9eb58 100644
--- a/package.json
+++ b/package.json
@@ -30,6 +30,7 @@
     "class-transformer": "^0.2.3",
     "class-validator": "^0.12.2",
     "connect-typeorm": "^1.1.4",
+    "file-type": "^15.0.1",
     "raw-body": "^2.4.1",
     "reflect-metadata": "^0.1.13",
     "rimraf": "^3.0.2",
diff --git a/src/media/media.module.ts b/src/media/media.module.ts
index eebd3501a..f791218e4 100644
--- a/src/media/media.module.ts
+++ b/src/media/media.module.ts
@@ -1,8 +1,13 @@
 import { Module } from '@nestjs/common';
 import { TypeOrmModule } from '@nestjs/typeorm';
+import { NotesModule } from '../notes/notes.module';
+import { UsersModule } from '../users/users.module';
 import { MediaUpload } from './media-upload.entity';
+import { MediaService } from './media.service';
 
 @Module({
-  imports: [TypeOrmModule.forFeature([MediaUpload])],
+  imports: [TypeOrmModule.forFeature([MediaUpload]), NotesModule, UsersModule],
+  providers: [MediaService],
+  exports: [MediaService],
 })
 export class MediaModule {}
diff --git a/src/media/media.service.spec.ts b/src/media/media.service.spec.ts
new file mode 100644
index 000000000..5009e4a57
--- /dev/null
+++ b/src/media/media.service.spec.ts
@@ -0,0 +1,18 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { MediaService } from './media.service';
+
+describe('MediaService', () => {
+  let service: MediaService;
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [MediaService],
+    }).compile();
+
+    service = module.get<MediaService>(MediaService);
+  });
+
+  it('should be defined', () => {
+    expect(service).toBeDefined();
+  });
+});
diff --git a/src/media/media.service.ts b/src/media/media.service.ts
new file mode 100644
index 000000000..c8dfa2c3e
--- /dev/null
+++ b/src/media/media.service.ts
@@ -0,0 +1,52 @@
+import { Injectable } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import * as FileType from 'file-type';
+import { Repository } from 'typeorm';
+import { NotesService } from '../notes/notes.service';
+import { UsersService } from '../users/users.service';
+import { BackendType } from './backends/backend-type.enum';
+import { FilesystemBackend } from './backends/filesystem-backend';
+import { MediaUpload } from './media-upload.entity';
+import { MulterFile } from './multer-file.interface';
+
+@Injectable()
+export class MediaService {
+  constructor(
+    @InjectRepository(MediaUpload)
+    private mediaUploadRepository: Repository<MediaUpload>,
+    private notesService: NotesService,
+    private usersService: UsersService,
+  ) {}
+
+  public async saveFile(file: MulterFile, username: string, noteId: string) {
+    const note = await this.notesService.getNoteByIdOrAlias(noteId);
+    const user = await this.usersService.getUserByUsername(username);
+    const fileTypeResult = await FileType.fromBuffer(file.buffer);
+    if (!fileTypeResult) {
+      throw new Error('Could not detect file type.');
+    }
+    if (!MediaService.isAllowedMimeType(fileTypeResult.mime)) {
+      throw new Error('MIME type not allowed');
+    }
+    //TODO: Choose backend according to config
+    const mediaUpload = MediaUpload.create(
+      note,
+      user,
+      fileTypeResult.ext,
+      BackendType.FILEYSTEM,
+    );
+    const backend = new FilesystemBackend();
+    const [url, backendData] = await backend.saveFile(
+      file.buffer,
+      mediaUpload.id,
+    );
+    mediaUpload.backendData = backendData;
+    await this.mediaUploadRepository.save(mediaUpload);
+    return url;
+  }
+
+  private static isAllowedMimeType(mimeType: string): boolean {
+    //TODO: Which mimetypes are allowed?
+    return true;
+  }
+}
diff --git a/src/media/multer-file.interface.ts b/src/media/multer-file.interface.ts
new file mode 100644
index 000000000..a602a5008
--- /dev/null
+++ b/src/media/multer-file.interface.ts
@@ -0,0 +1,32 @@
+import { Readable } from 'stream';
+
+// Type from https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/multer/index.d.ts
+export interface MulterFile {
+  /** Name of the form field associated with this file. */
+  fieldname: string;
+  /** Name of the file on the uploader's computer. */
+  originalname: string;
+  /**
+   * Value of the `Content-Transfer-Encoding` header for this file.
+   * @deprecated since July 2015
+   * @see RFC 7578, Section 4.7
+   */
+  encoding: string;
+  /** Value of the `Content-Type` header for this file. */
+  mimetype: string;
+  /** Size of the file in bytes. */
+  size: number;
+  /**
+   * A readable stream of this file. Only available to the `_handleFile`
+   * callback for custom `StorageEngine`s.
+   */
+  stream: Readable;
+  /** `DiskStorage` only: Directory to which this file has been uploaded. */
+  destination: string;
+  /** `DiskStorage` only: Name of this file within `destination`. */
+  filename: string;
+  /** `DiskStorage` only: Full path to the uploaded file. */
+  path: string;
+  /** `MemoryStorage` only: A Buffer containing the entire file. */
+  buffer: Buffer;
+}