Robinhood Interview Questions

The most-reported Robinhood question by more than 3x, asked continuously across two years — and one candidate's phone-screen invite named "Job Scheduler" outright, so you can sometimes know the topic before the round starts. Cron-style recurring jobs, SLA violations, querying past runs, and fault tolerance everywhere. Reports are specific about what separates outcomes: passers guarantee at-most-once execution with conditional writes on the job-run row and cover worker crashes before being asked, while one rejection's recruiter feedback read simply "no workable fault tolerance solution." Expect the schema follow-up — tables, key columns, and types.

Parse service definitions into a dependency DAG, then compute how one unit of load on the entrypoint fans out — a service reachable along multiple paths counts every time. DFS solves it; the reported follow-up sequence is "where is the repeated work?", then implementing the topological-sort or memoised variant you mentioned, then complexity. The recorded failures are not conceptual: one candidate stalled on string parsing, another discovered mid-round that CoderPad's print output wasn't showing and couldn't debug without it. This is the free preview — full statement, follow-ups, and a solution run against its test cases.

Customers trade fractional shares but the broker can only move whole shares upstream, so you keep a per-ticker fractional inventory and decide when to transact with the exchange. One graded task plus a transaction-log follow-up the interviewer does not generally expect candidates to reach — secure part one first. The failure stories cut both ways: one candidate was penalized purely for pace with correct code, while another coded so fast, silently, that the interviewer suspected cheating and failed them. Robinhood's coding rounds grade working code and visible reasoning, not elegance.