Broken code. Fix it. 10
Production bugs with the artifacts you see on call: a failing test, a log excerpt, and broken code. Find the root cause, fix it, and compare your fix with the reference solution.
Backend debugging interview practice, answered
A debugging interview gives you broken, production-like code and a failing test. Then the interviewer watches how you find the root cause under time pressure. Senior Loop's bugs come from real incident patterns, such as race conditions, silent precision drift, retry storms, and broken idempotency. They cover payment systems, APIs, and distributed backends. The AI grades your diagnosis, not only whether the test passes.
What is a backend debugging interview?+−
You do not solve a whiteboard algorithm. You get real, broken production-style code and a failing test. You find and explain the root cause, as you would during an actual incident.
How is this different from LeetCode-style prep?+−
LeetCode tests algorithm recall in isolation. These bugs test root-cause reasoning in realistic backend systems. Senior and staff loops screen for this skill. A rubric of the real underlying failure grades your answer.
What kinds of bugs are included?+−
10+ real production bugs in payment systems, distributed systems, and APIs. They include race conditions, idempotency failures, precision drift, and other issues that senior engineers must catch fast.
Is debugging practice free?+−
Yes. 3 Bug Hunt exercises are free, and no card is required.