#retries

7 retries interview questions, asked at Amazon, Decagon, Mercor and 5 more companies. Last asked Oct 2026.

Make a charge-then-record payment flow safe against crashes and retriesCodingA backend first charges a customer through an external payment provider and then writes the payment to its own database. You are shown code like this (in Java or Python) and asked…
Last asked Oct 2026
Send requests in batches of five and retry failures after a delayCodingDeliver a list of requests to an API that accepts at most five requests per call. Some requests in a call can fail; a failed request may be retried only after its own delay has…
Last asked Sep 2026
Call a flaky HTTP API with Python requests and handle every errorCodingUsing Python's requests, write a client for a few endpoints of a fake API (you have its docs; the code does not need to run against a real server). Handle the failure cases…
Last asked Sep 2026
Precision and recall at k from a flaky top-k APICodingAn API returns a model's top-k predictions for each query, but calls sometimes fail or time out. Compute precision and recall against the true labels across a set of queries, with…
Last asked Feb 2026
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Design a webhook delivery systemSystem designDeliver event notifications to customers' HTTP endpoints at least once, with retries and backoff, signing, ordering where it matters, and isolation from slow endpoints.
Last asked Dec 2025
Design reliable sign-in on top of a flaky token providerSystem designClients get a token from a third-party auth server and present it to your main server. The third-party server is unreliable: requests fail sometimes, and sometimes it answers with…
Last asked Sep 2025
Make sure every cluster job completesSystem designA company runs many jobs on a high-performance cluster and needs a service that makes sure every one of them completes. You get two functions (for example, one that starts a job…
Last asked Jul 2025