Which browser should I use, and do I need to install anything?

Nothing to download

Everything happens on the website. The Factory, Brain code, the Test arena and the Arena all run in the page. Your test matches are simulated right in your browser, by the same simulation core the server uses for League matches, so a bot behaves the same way in a test as it does on the server.

Why Chrome or Edge

The big difference between browsers is how your code files are saved.

Chrome and Edge:

1. The first time you click Save on a file in Brain code, the browser asks where to put it.
2. After that, every Save writes straight to that file. No extra copies pile up.
3. Files you open with Open file… are saved back to the same file.
4. If a file you've opened changes on disk (for example, you pulled a teammate's changes, or edited it in another editor), Brain code reloads it by itself, as long as you have no unsaved changes to it.

Other browsers:

1. Save downloads a copy of the file.
2. Move it to the folder where you keep your bots' code yourself.
3. To keep working on it later, open it again with Open file….

Everything else (building, coding, testing, watching, the League) works the same.

3D views

The Factory shows your machine in 3D on a turntable. If your browser or computer can't show 3D graphics (WebGL), the 3D views are left out, but the Factory's build platform still works without them.

Keep the browser's storage on

While you're logged in, Brain code keeps your files in the browser too, under your account. If your browser blocks or clears site storage, that copy won't last, so always save your files with Save.