Pulse — Take-Home Assessment

Welcome, and thanks for taking the time. Pulse is a working (mostly!) Next.js app: a living globe of anonymous strangers — every online user is a dot on a world map; tap one to connect for text chat or a video call. No accounts, no history, nothing stored. Coordination and WebRTC signaling run through the server (Postgres + HTTP polling); chat and video are peer-to-peer over WebRTC.

You'll work through four phases. They're designed to be realistic, not trick questions. We care as much about how you think as about what you ship — so a short write-up is required (see Deliverables).

Using AI is allowed. Use whatever tools you'd use on the job. The phases are built so that judgment, debugging, and product taste matter more than raw code generation. Please make the decisions yours and be ready to explain them.

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See it live

A working version is deployed at https://pulse-silk-eta.vercel.app/.

Because Pulse connects two strangers, you need two participants to try it: open the link in two separate browser windows (e.g. a normal window + an incognito/private window, or two different browsers). In each window's DevTools → Sensors, set a different mock geolocation so the two dots land apart, then tap one dot to connect, accept, chat, and start video.

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How it works

• Coordination only runs on the server: live presence and the WebRTC signaling handshake, stored transiently in Postgres (via Prisma) and delivered by short HTTP polling (no WebSockets — they don't work on Vercel serverless).
• Chat and video are peer-to-peer over WebRTC (data channel + media). They never touch the server, so messages and video are never seen or stored.
• The map is Mapbox GL JS. Each dot is placed 1–3 km from the user's real location, randomized fresh every session.

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Getting started

⚠️ Repository setup — please read this first

Clone this repository — do NOT fork it. Then create a brand-new public GitHub repository of your own and push your clone there. Commit as you go — we review your git history and commit practice, so use meaningful, incremental commits with clear messages (not one giant final commit). Your final deliverables are your public repo URL and a live Vercel URL — see Deliverables below.

Local setup

1. Install deps:

   npm install
   

2. Copy .env.example to .env and fill in your own credentials:
   • A free Postgres database — Neon or Vercel Postgres.
   • A free Mapbox token.
3. Create the tables:

   npx prisma db push
   

4. Run it:

   npm run dev
   

   Open http://localhost:3000.

Testing with two users

WebRTC needs two participants. Open the app in two browser profiles (e.g. a normal window + an incognito window). In each tab's DevTools → Sensors, set a different mock geolocation so the dots land apart, then connect.

Connections use STUN only (no TURN), so a minority of strict/corporate networks won't establish a media connection — that's a known limitation, not something you need to solve.

There is a note in AGENTS.md about this codebase. Please read it.

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The phases

(See the email for time expectations.)

Phase 1 — Make it run

The app does not currently work end-to-end. There are several bugs in here — find and fix each one until two users can reliably see each other on the map, connect, chat, and start a video call.

As one example of the kind of thing you'll run into:

"I tested with a friend. After we both closed the app, our dots stayed on the map for ages — it kept looking like people were online when nobody was."

That's one bug. There are more — this is just an example to show the flavor. Track down and fix each issue you find.

Phase 2 — Make it good

This phase is all about UI/UX. Make Pulse genuinely beautiful — something you'd be proud to show off and that people would actually want to use. There's no mockup and no rules: restyle anything, add motion and polish, rethink the layout, tighten the flow, sweat the details. Use your creativity and make this app gorgeous. We're looking at your sense of design, taste, and product feel — go make it stunning.

Phase 3 — Make it secure

Review the API before shipping. Identify the issues you'd want fixed before this went live, prioritize them, and address what you can.

Phase 4 — Make it better

Build something new that makes Pulse feel more alive and/or safe — and that genuinely impresses us. Add a unique feature or capability of your own design: something creative and original that makes the app stand out and that you'd want a reviewer to remember. There's no spec and no right answer — the idea is entirely yours. Surprise us, ship it working, and explain your thinking in your notes.

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A note on sequencing

Phases 2 and 4 can be attempted at any time. Phase 3 (security review) assumes a running app, so it's most natural after Phase 1.

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Deliverables

1. A public GitHub repository. Clone this project (do not fork it) and push it to a brand-new public repo of your own. Commit as you go — we review your git history and commit practice, so meaningful, incremental commits with clear messages matter.
2. A live Vercel deployment. Deploy your finished app and include the URL so we can test it end-to-end. Set the same env vars from .env.example in the Vercel project settings, and run the Prisma schema against your database.
3. A NOTES.md at the repo root with a short section per phase:
   • Phase 1: what was broken, how you found it, how you fixed it.
   • Phase 2: what you changed and the thinking behind it.
   • Phase 3: the issues you found, how you'd rank them, and what you fixed.
   • Phase 4: what you built, why, and what you'd do next with more time.

Submit the repo URL and the Vercel URL. Keep NOTES.md concise — bullet points are fine. We read it closely.

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Ground rules

• Use any libraries, tools, or AI assistance you like.
• Don't worry about pixel-perfect polish or 100% completeness — we're looking at judgment, problem-solving, and how you make trade-offs.
• If something is ambiguous, make a reasonable call and note your assumption.
• Do optimization you want, its your decision to make.

Good luck — have fun with it.

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How it's scored

Phase	Weight
Phase 1 — Make it run	15%
Phase 2 — Make it good	30%
Phase 3 — Make it secure	20%
Phase 4 — Make it better	30%
Engineering practice & delivery	5%