Anthropic Coding Interview Questions
These are the 19 Anthropic coding interview questions AceOffer has reconstructed from candidate reports, sorted by how often each was reported. File Deduplication leads at 50×. Every question shows when it was last reported; the catalog refreshes monthly.
Part of the full catalog of Anthropic interview questions, covering every round.
Key facts
- •19 distinct coding questions indexed
- •262 candidate reports across those questions
- •Most reported: File Deduplication — 50× (last seen September 2026)
- •Refreshed monthly · last updated October 2026
Which Anthropic rounds ask coding questions?
Anthropic draws coding questions from the rounds below. Counts are distinct questions, not times asked.
Most reported: Banking System (OA) — 17×
Most reported: File Deduplication — 50×
Most reported: Web Crawler — 48×
Which Anthropic coding questions get asked most?
Sorted by candidate-report frequency. Click any question for the full breakdown.
| Question | Round | Reported | Last seen |
|---|---|---|---|
| File Deduplication Anthropic's most-reported coding question: fifty threads, asked at the onsite coding round and at the phone screen in roughly equal numbers. One… | Coding | 50× | September 2026 |
| Web CrawlerFree The phone-screen coding question of 2025, reported in forty-eight threads from January 2025 to September 2026, and the one most often paired… | Phone Screen | 48× | September 2026 |
| Profiling / Stack Trace Analysis Sampling profilers find the slow parts of a program by periodically recording the whole call stack. One candidate posted the prompt verbatim:… | Coding | 42× | September 2026 |
| Image Processing Pipeline One problem written in two steps, then spoken follow-ups: Coding Q1 in reports from October 2025 to September 2026, the phone screen… | Coding | 25× | September 2026 |
| Banking System (OA)Free Design and implement an in-memory banking system in Python on CodeSignal: one class, four progressive parts (CodeSignal calls them levels), 90 minutes… | OA | 17× | July 2026 |
| Distributed Mode/Median A distributed-computation coding round, Q4 in the candidate portal, asked at phone screens and onsites from April 2025 to September 2026. Reports… | Coding | 15× | September 2026 |
| LRU Cache You are given a working Python LRU cache and asked to extend it, not to build one from scratch: one reply calls… | Coding | 12× | July 2026 |
| In-Memory DatabaseFree The most reported Anthropic OA: twelve threads between May 2025 and July 2026, three of them quoting prompt text verbatim. A 90-minute… | OA | 12× | July 2026 |
| Tokenizer Implementation Coding Q6 in the candidate portal: eleven threads from February 2025 to July 2026, phone screens in most, one onsite coding round,… | Phone Screen | 11× | July 2026 |
| Task Management SystemFree A CodeSignal online assessment with no interviewer, five reports between January and August 2026 and a reply elsewhere naming it. Build one… | OA | 5× | August 2026 |
| AI-Assisted Coding: Four Pull Requests with Claude Code Format. A coding round done with AI tools. One report places it in the virtual onsite. The prompt candidates receive opens: This… | Coding | 4× | September 2026 |
| VLIW / TPU / Kernel Optimization AssignmentFree Take-home coding assignment (2–4 hours, AI usage permitted) for Anthropic's acceleration/performance engineering roles. You are given a Python-based VLIW or TPU simulator… | OA | 4× | December 2025 |
| Consecutive Event / Sample Detection A stream of Sample objects, each a numeric timestamp ts and an ordered list of elements, for example Sample(1, ['a', 'b']). The… | Phone Screen | 3× | December 2025 |
| Claude Agent Loop with Multi-Step Tool Calling The round: Anthropic's "Agents/Coding" interview, 55 minutes. A September 2025 thread quotes the portal as "A 55-minute coding on prompting and engineering… | Phone Screen | 3× | August 2026 |
| Bootloader with Loop Detection A new onsite coding question, three reports from June and July 2026. One candidate asked what "bootloader" meant and was told the… | Coding | 3× | July 2026 |
| Recipe ManagerFree A 90-minute CodeSignal OA with no interviewer, three threads between November 2025 and April 2026 plus one more naming it. One candidate… | OA | 3× | April 2026 |
| Cloud File Storage SystemFree A CodeSignal online assessment with no interviewer, one of the handful of questions in Anthropic's OA bank, mentioned in three threads between… | OA | 3× | July 2026 |
| Step-by-step Implementation (OA Part i)Free Implement functionality in 0-7 incremental steps with increasing difficulty. Topics include recursion, caching, and concurrency. Requires camera… | OA | 1× | June 2026 |
| Debugging Exercise (OA Part ii)Free | OA | 1× | June 2026 |
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