Open source · Python in the browser

Code together.
Stay sharp.

Run ensemble (mob) programming sessions in the browser: one shared editor, a rotating driver, navigator and timekeeper, and short timed segments with a debrief in between. No installs, no screen sharing.

Start a session

Share the link and your team joins from any browser. No idea what to code? Pick a starter challenge ↓

A session with Alice driving, Bob navigating and a highlighted traceback

See it in action

Alice and Bob solve FizzBuzz together in one minute.

Why code together

Everyone works on the same problem, at the same time, in one editor, whether you're a team or a learning community. It's one of the fastest ways to grow engineers and keep everyone close to the code.

🛠️

Stay technical

Leads and seniors keep their hands on the keyboard in short, regular turns instead of drifting into meetings.

🎓

Train engineers

Juniors drive while seniors navigate. Skills move through hands on the keyboard, not through docs nobody reads.

🧠

Share knowledge

Everyone sees every decision as it's made. No single owner, fewer handoffs and shorter review queues.

🥋

Practice on purpose

Run katas and coding dojos with a built-in timer and a debrief after every segment.

Need an idea? Start from a challenge

Free Python exercises with ready-made pytest tests. The session opens with the starter code, and Run tests shows how close the team is.

How it works

  1. 1

    Create a session

    Set a goal and share the link. Everyone joins from their browser.

  2. 2

    Join the rotation

    Take a turn as driver, navigator or timekeeper, or sit in as an observer to watch and learn.

  3. 3

    Code in segments

    The driver types, the navigator steers. When time is up, roles rotate and the team debriefs before the next segment.

Built for the way ensembles work

⚡ Live shared editor

Every keystroke streams to the whole team instantly.

⌨️ Driver-only typing

Ideas go through someone else's hands, the core rule of ensemble programming.

🐍 Python in your browser

Code runs locally via Pyodide, with highlighted tracebacks. Nothing runs on the server.

⏱️ Rotation timer

1–30 minute segments with a break to debrief, or keep rotating. Anyone can pause for interruptions.

👀 Observers

Managers, new hires or students can watch without taking a turn.

🔓 Open source

FastAPI, WebSockets and htmx. Read the code.

Ready for your first session?

Start a session