xAI interview questions for engineers

Reported interview periodNot available

Disk-backed map

Build a map whose values survive a process crash. A memory-only map does not meet the contract.

Practice focusget returns the stored value or nothing. put stores a pair and must reach disk before it returns. Startup reads the file and rebuilds the map. A torn or partial final line is ignored. Requirements - Part one is an append-only log. Each put adds one line. Startup replays the file. Never rewrite a line in place. - An update of an existing key appends a newer line. Replay keeps the last complete line for that key. - A second process that opens the same path must see committed values. - Part two is compaction.…

Free practice

Topic tags
Data structures

xAISystem designHalf AI-generated

Discussion / designResponse prompt

Reported interview periodNot available

Compressed prefix tree

Store sequences of integers so a shared beginning occupies one path. A plain trie uses one node per integer. Here, a run of nodes that each have only one child is stored as one edge.

Practice focusRequirements - Insert shares an edge when two sequences start the same way. A sequence with nothing in common gets its own branch. - Inserting a shorter sequence after a longer one must cut the long edge. - To cut an edge, walk until the new sequence disagrees. The shared head stays on the parent edge. The old tail becomes one child. The new tail becomes another. - A disagreement on the first integer splits that edge into a one-integer head plus two children. - Exact membership is true only for a sequence that was inserted, not for a proper head of one.…

Free practice

xAISystem designHalf AI-generated

Discussion / designResponse prompt

Reported interview periodNot available

Long video agent pipeline

Sketch a pipeline that turns a script into shots, frames, audio, and a cut. Name which agent owns each stage. The hard part is consistency: characters, places, and props must hold across many scenes. Pacing is …

Practice focusRequirements - Use a scene record, character sheets, and a continuity tracker as shared memory. - Split the work into a director that turns a script into a shot list, a continuity agent that keeps a vector per character and prop, a renderer that calls a video model conditioned on both, and an editor that reviews cuts and pace. - Inside one clip, rely on the video model to keep a subject that leaves and re-enters the frame. Do not rebuild that part.…

Free practice

Topic tags
Algorithms
Product design

xAISystem designHalf AI-generated

Discussion / designResponse prompt

Reported interview periodNot available

Split matrix product

Compute the product of two matrices on a group of devices, two ways, and compare both results with a product computed on one device.

Practice focusRequirements - The device count divides both dimensions. One device is the local product. - Data-parallel: each device multiplies its row slice of the left matrix by the full right matrix and sends that block to rank zero, which stacks the rows. - Sharded: the left matrix is split by rows and the right matrix by columns. Over as many rounds as there are devices, each device passes its right-hand shard to the neighbor and adds that partial into the matching columns of the piece it keeps. - The communicator is a set of blocking queues.…

Free practice

Topic tags
Data structures
ML / AI
Communication

xAISystem designHalf AI-generated

Discussion / designResponse prompt

Reported interview periodNot available

Real-time inference gateway

Design a gateway for low-latency model inference across several model versions and accelerator pools. Include admission control, routing, batching, deadlines, retries, overload behavior, observability, and safe…

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.…

Public brief

Topic tags
ML / AI

xAISystem designHalf AI-generated

Discussion / designResponse prompt

Reported interview periodNot available

Checkers backend

Model an eight-by-eight board. Each piece is one side's, and each piece is regular or king. There is no hidden grader. The work is the data model and the method boundaries.

Practice focusRequirements - A move check confirms the piece belongs to the player, the destination is empty, the step is diagonal, and the direction matches the piece type. - A capture jumps an opposing piece and may continue in a chain. - A piece that reaches the far row becomes a king. - The game ends when the opponent has no pieces or no legal move. - Represent the board as a grid of optional pieces. - Say whether each move returns a new board or changes the old one.…

Public brief

Topic tags
Reliability
ML / AI
Data / SQL

System designSystem designAI-generated

Written response70–90 min

Reported interview periodN/A

Design an evaluation artifact registry

Design a reproducible registry connecting datasets, evaluator configurations, model outputs, and reviewed results.

Practice focusData lineage, Versioning, Idempotency, Access control, Reproducibility through a written response exercise.

Public brief

Topic tags
Concurrency
Reliability
Security
Product design

xAISystem designAI-generated

Written response45–60 min

Reported interview periodN/A

Design durable scheduled publishing

A posting product lets an author write now and publish later. Design the path from submission to publication, then keep it correct when authors edit, cancel, and retry while delivery fans out to followers.

Practice focusDurable scheduling, Idempotency, Race conditions, Time zones, Operational telemetry through a written response exercise.

Public brief

Topic tags
ML / AI

xAISystem designAI-generated

Written response45–60 min

Reported interview periodN/A

Make speculative code edits safe to accept

A code-generation path drafts edits and a stronger model checks them. Decide which spans are accepted or rolled back, keep the result correct, and show whether the second pass actually saves time.

Practice focusSpeculative execution, Verification design, Rollback, Correctness, Benchmarking through a written response exercise.

Public brief

Topic tags
Algorithms
Reliability

xAISystem designAI-generated

Written response45–60 min

Reported interview periodN/A

Recover a grouping rule from two-word phrases

You get a short list of accepted two-word phrases and a batch of strings. Infer the rule that decides which strings belong together, implement it so the same input always yields the same partition, and say where the examples still underdetermine the answer.

Practice focusString algorithms, Specification recovery, Determinism, Edge-case analysis through a written response exercise.

xAI interview questions for engineering roles

xAI interview questions for engineering roles

What candidates report about the interview

Disk-backed map

Compressed prefix tree

Long video agent pipeline

Split matrix product

Real-time inference gateway

Checkers backend

Design an evaluation artifact registry

Design durable scheduled publishing

Make speculative code edits safe to accept

Recover a grouping rule from two-word phrases

What candidates report about the interview

Disk-backed map

Compressed prefix tree

Long video agent pipeline

Split matrix product

Real-time inference gateway

Checkers backend

Design an evaluation artifact registry

Design durable scheduled publishing

Make speculative code edits safe to accept

Recover a grouping rule from two-word phrases