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Cover image for I built a coding-interview platform solo — live video + a shared editor + anti-cheat (WebRTC + CRDT + Judge0)
Daksh khosla
Daksh khosla

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I built a coding-interview platform solo — live video + a shared editor + anti-cheat (WebRTC + CRDT + Judge0)

What it does:

  • Live video + a shared code editor both people type in at the same time. The editor sync is a hand-rolled CRDT over a WebRTC data channel, so no server round-trips and no edit conflicts.

  • Run code in the browser — JavaScript, Python, Dart, C++ — output shown to both sides instantly (via Judge0).

  • Activity monitoring — the interviewer sees when a candidate switches tabs, opens an overlay, or leaves the app, with a live event log. After 3 flags they can end the interview. Not trying to be Big Brother — just making cheating visible instead of guessed.

  • Built-in chat, one-tap invite links, and a per-candidate rating + notes history tagged by role.

Stack: Flutter (web + mobile), WebRTC for P2P media/data, Firebase for auth + signaling, Judge0 for execution. Built solo over a lot of late nights.

Honest rough edge: it's fully peer-to-peer, which is great for latency/cost/privacy, but strict corporate/college Wi-Fi firewalls can block P2P — so for now it works most reliably on mobile data / home Wi-Fi. Proper relay (TURN) support is my next big task.

👉 Try it: https://vyntra.space — open it, host a room, send the code to a second tab or a friend, and run a mock interview. Takes about a minute.

What I'd love feedback on: whether the anti-cheat monitoring feels fair or creepy, and what would make you actually switch from your current interview setup.

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