Docker Development


Debian-based distro:

sudo apt install git docker-compose
sudo systemctl start docker
git clone --recursive

Arch-based distro:

sudo pacman -S git docker-compose
sudo systemctl start docker

Get the code with submodules:

git clone --recursive


cd docker

Then open localhost:1236 in your browser.

Building with Docker is relatively slow. To get faster builds you need to use local development instead.

Federation Development

The federation setup allows starting a few local Lemmy instances, to test federation functionality. You can start it with the following commands:

cd docker/federation

The federation test sets up 5 instances:

InstanceAdmin usernameLocationNotes
lemmy-alphalemmy_alpha127.0.0.1:8540federated with all other instances
lemmy-betalemmy_beta127.0.0.1:8550federated with all other instances
lemmy-gammalemmy_gamma127.0.0.1:8560federated with all other instances
lemmy-deltalemmy_delta127.0.0.1:8570only allows federation with lemmy-beta
lemmy-epsilonlemmy_epsilon127.0.0.1:8580uses blocklist, has lemmy-alpha blocked

You can log into each using the instance name, and lemmy as the password, IE (lemmy_alpha, lemmy).

To start federation between instances, visit one of them and search for a user, community or post, like this. Note that the Lemmy backend runs on a different port than the frontend, so you have to increment the port number from the URL bar by one.

  • http://lemmy-gamma:8561/u/lemmy-gamma
  • http://lemmy-alpha:8541/c/main
  • http://lemmy-beta:8551/post/3