+### Client and server side
+
+The API will listen on `localhost:9000` and the frontend on `localhost:3000`.
+File changes are automatically recompiled, injected in the web browser (no need to refresh manually)
+and the web server is automatically restarted.
+
+```
+$ npm run dev
+```
+
+### RTL layout
+
+To test RTL layout using `ar` locale:
+
+```
+$ npm run dev -- --ar-locale
+```
+
+### Testing
+
+#### Unit/integration tests
+
+Your code contributions must pass the tests before they can be merged. Tests ensure most of the application behaves
+as expected and respect the syntax conventions. They will run upon PR submission as part of our CI, but running them beforehand yourself will get you faster feedback and save CI runner time for others.
+
+See the [dedicated documentation](/support/doc/development/tests.md) to run tests locally.
+
+#### Testing the federation of PeerTube servers
+
+Create a PostgreSQL user **with the same name as your username** in order to avoid using the *postgres* user.
+Then, we can create the databases (if they don't already exist):
+
+```
+$ sudo -u postgres createuser you_username --createdb
+$ createdb -O peertube peertube_test{1,2,3}
+```