Codebase rounds

More interviews now drop you into an existing codebase with an AI assistant instead of a blank editor. Each round is a small Python repo in three phases: fix a bug, build a feature from a ticket, then make it fast enough for a big hidden test. Bring your own AI; hidden tests grade the work.

How AI-assisted coding interviews work, and how to approach them →

• Courier maze

  A delivery-robot router whose routes cut through the outer wall, one-way gates from a product spec, then a warehouse with six keys where the route search never finishes.

  hard 60 min Python Meta AI-enabled coding-style

• Order pages

  A small shop backend: a pagination bug customers can see, a bulk-discount feature from a PRD, then a monthly report that falls over at 200,000 orders.

  medium 60 min Python Stripe Bug Squash-styleMeta AI-enabled coding-style

• Rate limiter

  An API gateway that lets merchants blow past their limit, a PRD for per-merchant limits and Retry-After, then a limiter that crawls once a big merchant sends 50,000 requests a minute.

  medium 60 min Python Shopify-styleStripe Bug Squash-style

Each round is checked by hidden tests on our judge. Your code runs in a sandbox with no network.