Pulse is a real, running realtime chat app with three seeded bugs in its message-ordering, unread-count, and reconnect logic. You're handed a ticket, open a real GitHub pull request against the actual bug, an AI teammate reviews your diff like a coworker would, and a hidden test suite decides — objectively — whether your fix works.
Real GitHub PRs · Graded by tests, not vibes · Certificate on completion
This isn't a lesson plan. You clone Pulse, a working realtime chat app with channels, a WebSocket message layer, and reconnect handling. You're handed a ticket describing a real reported bug, you read the relevant code, fix it, and open a pull request. An AI teammate reviews the PR in the thread. A hidden test suite tells you whether it's actually fixed.
Messages are appended to the UI in the order their network responses arrive, not in server-authoritative order — so under rapid sends, a later message can resolve first and jump ahead, and optimistic local echoes never reconcile to their eventual server position. Passing requires messages to display in server-authoritative order regardless of response timing, with optimistic echoes reconciling cleanly and no duplicates appearing once they do.
The unread counter bumps on every incoming message, including the channel the user currently has open and focused — the reset logic only fires on the initial channel-switch, not while a message arrives during an active session. Passing requires a focused channel's unread count to stay at zero while background channels still increment normally, verified against the hidden suite's focus-state matrix.
The socket client resumes after a drop by just resubscribing to live events — there's no backfill of anything sent while it was disconnected, so messages from the outage window vanish with no gap indicator. Passing requires the client to backfill from a last-seen cursor with no gaps and no duplicates, and message ordering to hold across the reconnect boundary.
Every Pulse ticket ships with a hidden, authoritative test suite — the same kind of check that gates a PR in a real CI pipeline. That suite, not a human's impression, decides whether your fix passes.
Pulse assumes you already know TypeScript and basic async/event-driven concepts — it's testing whether you can debug concurrency and ordering bugs inside someone else's codebase, not teaching you the language from zero.
Backend and full-stack devs whose portfolio has never included a real concurrency or ordering bug, only CRUD.
Engineers who've used WebSockets or Socket.io in a tutorial but never had to debug message-ordering or reconnect logic under load.
Anyone prepping for interviews who wants to say “I fixed a reconnect data-loss bug” instead of “I built a chat app clone.”
Developers who've never had a real code review and want to feel what an actual “request changes” comment is like before it happens on the job.
Not for: day-one beginners with no TypeScript or async-programming fundamentals — Pulse tests debugging inside an existing realtime codebase, not language basics.
No. There's no video, no lesson, no multiple choice. You get a ticket describing a real bug in a real running chat app, and you fix it by opening a real GitHub pull request. Everything after that — review, grading — happens the way it would on an actual team.
An AI teammate reviews the diff in the PR thread the way a coworker would — asking questions, flagging issues, requesting changes. Whether your fix is actually correct is decided separately, by a hidden automated test suite, so the outcome isn't a matter of the reviewer's opinion.
You get the failing test output — what passed, what didn't — and you keep iterating on the PR until it passes, same as you would against CI on a real team.
Yes. Completed tickets and tracked hours generate a certificate with a public, verifiable link, built for exactly that.
It's sized like a sprint's worth of real tickets, not a single afternoon exercise — expect to spend real, trackable hours across RT-601, RT-607, and RT-613, the same way you'd clear a sprint backlog.
Yes — this tests and builds your ability to debug and ship inside an existing codebase, not to learn the language for the first time.
LeetCode tests algorithm recall in isolation. A bootcamp capstone is usually a solo project nobody reviews. Pulse is someone else's codebase, with a real bug, a real PR, a real reviewer, and a real pass/fail bar — the actual shape of the job.