diff --git a/package.json b/package.json
index 9bda3ca6e..0fd29feaf 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
   },
   "dependencies": {
     "@nestjs/common": "7.6.5",
+    "@nestjs/config": "^0.6.1",
     "@nestjs/core": "7.6.5",
     "@nestjs/platform-express": "7.6.5",
     "@nestjs/swagger": "4.7.10",
@@ -34,6 +35,7 @@
     "cli-color": "2.0.0",
     "connect-typeorm": "1.1.4",
     "file-type": "16.2.0",
+    "joi": "^17.3.0",
     "raw-body": "2.4.1",
     "reflect-metadata": "0.1.13",
     "rimraf": "3.0.2",
diff --git a/src/app.module.ts b/src/app.module.ts
index 3cef03730..a693d86a1 100644
--- a/src/app.module.ts
+++ b/src/app.module.ts
@@ -5,6 +5,7 @@
  */
 
 import { Module } from '@nestjs/common';
+import { ConfigModule } from '@nestjs/config';
 import { TypeOrmModule } from '@nestjs/typeorm';
 import { PublicApiModule } from './api/public/public-api.module';
 import { AuthorsModule } from './authors/authors.module';
@@ -17,6 +18,7 @@ import { NotesModule } from './notes/notes.module';
 import { PermissionsModule } from './permissions/permissions.module';
 import { RevisionsModule } from './revisions/revisions.module';
 import { UsersModule } from './users/users.module';
+import appConfig from './config/app.config';
 
 @Module({
   imports: [
@@ -26,6 +28,9 @@ import { UsersModule } from './users/users.module';
       autoLoadEntities: true,
       synchronize: true,
     }),
+    ConfigModule.forRoot({
+      load: [appConfig],
+    }),
     NotesModule,
     UsersModule,
     RevisionsModule,
diff --git a/src/config/app.config.ts b/src/config/app.config.ts
new file mode 100644
index 000000000..122fda6f9
--- /dev/null
+++ b/src/config/app.config.ts
@@ -0,0 +1,60 @@
+/*
+ * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { registerAs } from '@nestjs/config';
+import * as Joi from 'joi';
+
+export interface AppConfig {
+  port: number;
+  media: {
+    backend: {
+      use: string;
+      filesystem: {
+        uploadPath: string;
+      };
+    };
+  };
+}
+
+const schema = Joi.object({
+  port: Joi.number(),
+  media: {
+    backend: {
+      use: Joi.string().valid('filesystem'),
+      filesystem: {
+        uploadPath: Joi.when('...use', {
+          is: Joi.valid('filesystem'),
+          then: Joi.string(),
+          otherwise: Joi.optional(),
+        }),
+      },
+    },
+  },
+});
+
+export default registerAs('appConfig', async () => {
+  const appConfig = schema.validate(
+    {
+      port: parseInt(process.env.PORT) || undefined,
+      media: {
+        backend: {
+          use: process.env.HD_MEDIA_BACKEND,
+          filesystem: {
+            uploadPath: process.env.HD_MEDIA_BACKEND_FILESYSTEM_UPLOAD_PATH,
+          },
+        },
+      },
+    },
+    {
+      abortEarly: false,
+      presence: 'required',
+    },
+  );
+  if (appConfig.error) {
+    throw new Error(appConfig.error.toString());
+  }
+  return appConfig.value;
+});
diff --git a/yarn.lock b/yarn.lock
index a2365d24e..a44462f45 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -367,6 +367,18 @@
     minimatch "^3.0.4"
     strip-json-comments "^3.1.1"
 
+"@hapi/hoek@^9.0.0":
+  version "9.1.1"
+  resolved "https://registry.yarnpkg.com/@hapi/hoek/-/hoek-9.1.1.tgz#9daf5745156fd84b8e9889a2dc721f0c58e894aa"
+  integrity sha512-CAEbWH7OIur6jEOzaai83jq3FmKmv4PmX1JYfs9IrYcGEVI/lyL1EXJGCj7eFVJ0bg5QR8LMxBlEtA+xKiLpFw==
+
+"@hapi/topo@^5.0.0":
+  version "5.0.0"
+  resolved "https://registry.yarnpkg.com/@hapi/topo/-/topo-5.0.0.tgz#c19af8577fa393a06e9c77b60995af959be721e7"
+  integrity sha512-tFJlT47db0kMqVm3H4nQYgn6Pwg10GTZHb1pwmSiv1K4ks6drQOtfEF5ZnPjkvC+y4/bUPHK+bc87QvLcL+WMw==
+  dependencies:
+    "@hapi/hoek" "^9.0.0"
+
 "@istanbuljs/load-nyc-config@^1.0.0":
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/@istanbuljs/load-nyc-config/-/load-nyc-config-1.1.0.tgz#fd3db1d59ecf7cf121e80650bb86712f9b55eced"
@@ -592,6 +604,18 @@
     tslib "2.0.3"
     uuid "8.3.2"
 
+"@nestjs/config@^0.6.1":
+  version "0.6.1"
+  resolved "https://registry.yarnpkg.com/@nestjs/config/-/config-0.6.1.tgz#26e4bfd4b2f9d3a6b6bed6445a2a1e766abdf1c6"
+  integrity sha512-sSIEbHp0xV7bneG2/CePqJh60ELojsBXBPuRM40AcVQwuDRQQ4RAnLT5uaJbWB2xFQjQwik4zejN+27t1cCiBQ==
+  dependencies:
+    dotenv "8.2.0"
+    dotenv-expand "5.1.0"
+    lodash.get "4.4.2"
+    lodash.has "4.5.2"
+    lodash.set "4.3.2"
+    uuid "8.3.1"
+
 "@nestjs/core@7.6.5":
   version "7.6.5"
   resolved "https://registry.yarnpkg.com/@nestjs/core/-/core-7.6.5.tgz#93c642d1abf8d3f09f8f78c262814eaf83bc2ad6"
@@ -703,6 +727,23 @@
     "@angular-devkit/core" "11.0.3"
     "@angular-devkit/schematics" "11.0.3"
 
+"@sideway/address@^4.1.0":
+  version "4.1.0"
+  resolved "https://registry.yarnpkg.com/@sideway/address/-/address-4.1.0.tgz#0b301ada10ac4e0e3fa525c90615e0b61a72b78d"
+  integrity sha512-wAH/JYRXeIFQRsxerIuLjgUu2Xszam+O5xKeatJ4oudShOOirfmsQ1D6LL54XOU2tizpCYku+s1wmU0SYdpoSA==
+  dependencies:
+    "@hapi/hoek" "^9.0.0"
+
+"@sideway/formula@^3.0.0":
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/@sideway/formula/-/formula-3.0.0.tgz#fe158aee32e6bd5de85044be615bc08478a0a13c"
+  integrity sha512-vHe7wZ4NOXVfkoRb8T5otiENVlT7a3IAiw7H5M2+GO+9CDgcVUUsX1zalAztCmwyOr2RUTGJdgB+ZvSVqmdHmg==
+
+"@sideway/pinpoint@^2.0.0":
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/@sideway/pinpoint/-/pinpoint-2.0.0.tgz#cff8ffadc372ad29fd3f78277aeb29e632cc70df"
+  integrity sha512-RNiOoTPkptFtSVzQevY/yWtZwf/RxyVnPy/OcA9HBM3MlGDnBEYL5B41H0MTn0Uec8Hi+2qUtTfG2WWZBmMejQ==
+
 "@sinonjs/commons@^1.7.0":
   version "1.7.2"
   resolved "https://registry.yarnpkg.com/@sinonjs/commons/-/commons-1.7.2.tgz#505f55c74e0272b43f6c52d81946bed7058fc0e2"
@@ -2454,7 +2495,12 @@ domexception@^2.0.1:
   dependencies:
     webidl-conversions "^5.0.0"
 
-dotenv@^8.2.0:
+dotenv-expand@5.1.0:
+  version "5.1.0"
+  resolved "https://registry.yarnpkg.com/dotenv-expand/-/dotenv-expand-5.1.0.tgz#3fbaf020bfd794884072ea26b1e9791d45a629f0"
+  integrity sha512-YXQl1DSa4/PQyRfgrv6aoNjhasp/p4qs9FjJ4q4cQk+8m4r6k4ZSiEyytKG8f8W9gi8WsQtIObNmKd+tMzNTmA==
+
+dotenv@8.2.0, dotenv@^8.2.0:
   version "8.2.0"
   resolved "https://registry.yarnpkg.com/dotenv/-/dotenv-8.2.0.tgz#97e619259ada750eea3e4ea3e26bceea5424b16a"
   integrity sha512-8sJ78ElpbDJBHNeBzUbUVLsqKdccaa/BXF1uPTw3GrvQTBgrQrtObr2mUrE38vzYd8cEv+m/JBfDLioYcfXoaw==
@@ -4344,6 +4390,17 @@ jest@26.6.3:
     import-local "^3.0.2"
     jest-cli "^26.6.3"
 
+joi@^17.3.0:
+  version "17.3.0"
+  resolved "https://registry.yarnpkg.com/joi/-/joi-17.3.0.tgz#f1be4a6ce29bc1716665819ac361dfa139fff5d2"
+  integrity sha512-Qh5gdU6niuYbUIUV5ejbsMiiFmBdw8Kcp8Buj2JntszCkCfxJ9Cz76OtHxOZMPXrt5810iDIXs+n1nNVoquHgg==
+  dependencies:
+    "@hapi/hoek" "^9.0.0"
+    "@hapi/topo" "^5.0.0"
+    "@sideway/address" "^4.1.0"
+    "@sideway/formula" "^3.0.0"
+    "@sideway/pinpoint" "^2.0.0"
+
 js-tokens@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-4.0.0.tgz#19203fb59991df98e3a287050d4647cdeaf32499"
@@ -4566,11 +4623,26 @@ locate-path@^5.0.0:
   dependencies:
     p-locate "^4.1.0"
 
+lodash.get@4.4.2:
+  version "4.4.2"
+  resolved "https://registry.yarnpkg.com/lodash.get/-/lodash.get-4.4.2.tgz#2d177f652fa31e939b4438d5341499dfa3825e99"
+  integrity sha1-LRd/ZS+jHpObRDjVNBSZ36OCXpk=
+
+lodash.has@4.5.2:
+  version "4.5.2"
+  resolved "https://registry.yarnpkg.com/lodash.has/-/lodash.has-4.5.2.tgz#d19f4dc1095058cccbe2b0cdf4ee0fe4aa37c862"
+  integrity sha1-0Z9NwQlQWMzL4rDN9O4P5Ko3yGI=
+
 lodash.memoize@4.x:
   version "4.1.2"
   resolved "https://registry.yarnpkg.com/lodash.memoize/-/lodash.memoize-4.1.2.tgz#bcc6c49a42a2840ed997f323eada5ecd182e0bfe"
   integrity sha1-vMbEmkKihA7Zl/Mj6tpezRguC/4=
 
+lodash.set@4.3.2:
+  version "4.3.2"
+  resolved "https://registry.yarnpkg.com/lodash.set/-/lodash.set-4.3.2.tgz#d8757b1da807dde24816b0d6a84bea1a76230b23"
+  integrity sha1-2HV7HagH3eJIFrDWqEvqGnYjCyM=
+
 lodash.sortby@^4.7.0:
   version "4.7.0"
   resolved "https://registry.yarnpkg.com/lodash.sortby/-/lodash.sortby-4.7.0.tgz#edd14c824e2cc9c1e0b0a1b42bb5210516a42438"