Broken code. Failing tests. Fix it.
10 bugs · 5 languages10 available
Production bugs with the artifacts you'd see on call — failing test, log excerpt, broken code. Pick the language you think in.
Order pagination returns duplicate rows
freeThe /orders endpoint returns the same order on two consecutive pages. Find the off-by-one and fix it.
Ledger drift after refund retry
freeA refund retry occasionally produces a ledger entry where the refund is recorded twice but the wallet was credited once. Find the bug and fix it.
Click-tracking counter drops events under load
freeClick-tracking endpoint occasionally undercounts events. Some events vanish, others crash the concurrent handler that increments. Find the bug and fix it.
Validation endpoint p99 climbs under load
🔒The /validate endpoint's p99 latency climbs from 8ms to 280ms once traffic crosses 500 RPS. Find the hot-path waste and fix it.
Daily summary email arrives on the wrong day
🔒Users complain that their "yesterday's activity" email shows today's data, or skips a day entirely. Find the timezone bug.
JWT verification accepts forged tokens
🔒Security team filed a P1: an attacker can forge admin tokens against the auth middleware. Find the verification flaw and fix it.
Worker pool leaks background workers on shutdown
🔒A worker pool that processes background jobs leaks background workers on every service restart. Find what's wrong with the lifecycle.
User profile endpoint accepts privilege escalation
🔒PATCH /users/me lets a regular user upgrade themselves to admin by sending `{"role": "admin"}` in the body. Find the mass-assignment flaw and fix it.
Background-task spans become orphans in tracing
🔒Distributed traces show order-creation as a clean parent span, but the email-send and audit-log operations dispatched after the order appear as detached root spans with no parent. Find the propagation bug.
Idempotency cache returns the wrong customer's response
🔒Customer A submits a charge. Customer B submits a charge a few minutes later and gets back Customer A's payment confirmation. Find the cross-tenant leak in the idempotency layer.