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Practice coding, system design, behavioral, and project questions for frontier AI roles.
Every question has a public brief with the task, constraints, and follow-ups. Labels describe interactive practice access.
Reported interview periodNot available
Two people edit one note and both need to see the last line that was saved.
Practice focusSystem design round. Two people share one note. Say where the note is stored. Say what both people see when they save the same line. Say what the second person sees when their save does not land. Stop when a third person can only read.
Reported interview periodNot available
Two people edit one note and need to see who wrote the last line.
Practice focusSystem design round. Two people share one scratch pad during a review. Start by listing what must be true: neither person loses a line, and both can point at who wrote the last line. Place the note in one store and give each save a version. Walk the case where both save the same version. Then the network drops the second save: the first person must not think the second line landed. Then add a third reader who only watches. Say what that reader sees, what you store, and what you would not build for a note this small.
Reported interview periodNot available
Two people edit one note and need to see who wrote the last line.
Practice focusSystem design round. Two people share one scratch pad during a review. Start by listing what must be true: neither person loses a line, and both can point at who wrote the last line. Place the note in one store and give each save a version. Walk the case where both save the same version. Then the network drops the second save: the first person must not think the second line landed. Then add a third reader who only watches. Say what that reader sees, what you store, and what you would not build for a note this small.
Reported interview periodNot available
Two people edit one note and need to see who wrote the last line.
Practice focusSystem design round. Two people share one scratch pad during a review. Start by listing what must be true: neither person loses a line, and both can point at who wrote the last line. Place the note in one store and give each save a version. Walk the case where both save the same version. Then the network drops the second save: the first person must not think the second line landed. Then add a third reader who only watches. Say what that reader sees, what you store, and what you would not build for a note this small.
Reported interview periodNot available
A team can improve model quality, reduce latency, or make failures easier to understand, but can fund only one this quarter. Choose a direction, state the users and evidence behind it, and define what would inv…
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
Walk through a project where you reduced latency or cost without weakening correctness. Cover the baseline, bottleneck, alternatives, the change you owned, rollout safeguards, and measured result.
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
Explain why a high-ownership role fits you using one project where you found an unowned problem, chose a direction, and delivered a measurable result. State the boundary of your authority and when you asked for…
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
Walk through a project where scale exposed a bottleneck. Cover the workload, the measured limit, your model of the bottleneck, the intervention you owned, and the evidence that the limit moved.
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodSep 2026
Design a service that ingests telemetry from many devices, detects meaningful state changes, and triggers control actions according to configurable rules.
Practice focusCover the ingestion API, event schema, message transport, stream processing, state storage, rule evaluation, and command-delivery path. Explain how the system handles bursty traffic, duplicate and out-of-order events, intermittent device connectivity, failed control commands, and service recovery. Define the latency and consistency guarantees you would offer, the metrics needed to operate the system, and the safeguards that prevent unstable feedback loops. Follow-ups 1. Support devices that remain offline for days and later upload buffered telemetry. 2.…
Reported interview periodFeb 2026–Sep 2026
Design a browser-based development environment where users can open persistent workspaces, edit files, run programs, and interact with a live terminal.
Practice focusCover workspace storage, process isolation, scheduling, standard-output streaming, terminal input, reconnect after refresh, dependency setup, and file synchronization. Explain how you prevent one user’s code from affecting another user or the host system. Address cold-start latency, idle-workspace suspension, resource quotas, long-running jobs, failure recovery, observability, and the trade-off between warm capacity and infrastructure cost. Follow-ups 1. Support collaborative editing without coupling file consistency to terminal I/O. 2.…
Reported interview periodFeb 2026–Sep 2026
Design a service that matches two players, maintains authoritative legal game state, supports clocks, and allows games to be reviewed later.
Practice focusRequirements - Define APIs or real-time events for matchmaking, moves, resignations, draw offers, reconnects, and spectators. - The server—not the client—validates turns, legal moves, check, checkmate, stalemate, and special rules. - Make duplicate or reordered client messages idempotent. - Maintain fair clocks despite network delay and disconnects. - Persist an append-only move history and enough state for fast reconnect and review. - State scale assumptions, latency goals, and consistency boundaries.…
Reported interview periodOct 2025–Jul 2026
Design the backend for a production chat assistant used concurrently by many customers. It should stream model output, invoke approved tools, preserve conversation state, and remain useful under model or depend…
Practice focusRequirements - Define APIs for creating conversations, sending messages, streaming events, cancelling work, and retrieving history. - Isolate tenants and authorize every history or tool access. - Orchestrate model calls and tool calls with timeouts, retries, idempotency, and bounded loops. - Enforce rate limits, quotas, content policy, and cost budgets. - Store message lineage, model/tool versions, and audit data without leaking sensitive prompts. - Set explicit latency, scale, durability, and availability targets.…
Reported interview periodNot available
Ten people store one score per run and look at which run is ahead this week.
Practice focusSystem design round. Ten people record one score per run. Say what a week means and what a missing score shows. Walk the write and the read. A score arrives twice for the same run. Keep the first. Stop when the board can say this week is still open.
Reported interview periodN/A
Review staged prompts that begin with a small in-memory worker, then introduce retries, duplication, cancellation, and process restarts.
Practice focusState modeling, Idempotency, Retry policy, Failure recovery, Operational reasoning through a written response exercise.
Reported interview periodN/A
Design a sequence that stays fast to index, accepts mutation, and can crash at any point without losing the state a reader already saw. Then make the restart path provable rather than plausible.
Practice focusData structure design, Complexity analysis, Durability, Crash recovery through a written response exercise.
Reported interview periodN/A
Two people edit one note and need to see who wrote the last line.
Practice focusConflict, Failure through a written response exercise.
Reported interview periodN/A
Store a score per model run and show which run is ahead this week.
Practice focusRead path, Write path through a written response exercise.