Anthropic Interview Questions — Page 28

Anthropic·Software Engineer·Technical Phone Screen

Jun 2026

Interviewed for a SWE role at Anthropic and got a system design question about building a multi-threaded web crawler. Pretty classic problem but there's a lot of surface area to cover and I don't think I hit all of it.

Design a web crawler that supports multi-threading.

“I started with the single-threaded version and then layered in concurrency, which felt like the right move, but I fumbled a bit on the coordination piece.”

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Anthropic·Software Engineer·Technical Phone Screen

Jun 2026

Coding round at Anthropic for a software engineer role, focused on graph traversal with a real system design twist baked in. The multithreaded follow-up is where things got interesting.

Implement a single-domain web crawler: given a starting URL and an interface that fetches all linked URLs from a page, return every reachable URL that shares the same hostname as the start URL, with no duplicates.
How would you parallelize the crawler using a thread pool, and what are the key concerns around concurrency, shared state, and knowing when the crawl is actually done?

“BFS felt like the obvious move so I went with that, queue plus a visited set.”

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Anthropic·Software Engineer·Technical Phone Screen

Jun 2026

Anthropic SWE interview that started with a classic BFS web crawler and then pivoted hard into concurrency design. The single-threaded part felt manageable but the follow-up questions on parallelization were where things got interesting.

Implement a single-threaded web crawler that starts from a given URL, discovers all reachable pages within the same domain using BFS, and avoids revisiting pages. Include URL normalization, same-domain filtering, and a page or depth cap.
How would you parallelize the crawler using a thread pool? Describe the producer/consumer structure and how you'd make the shared visited set and queue thread-safe.
When is multithreading the right choice for this kind of workload versus multiprocessing, given Python's GIL?
How do you gracefully shut down the crawler when the queue is empty but some worker threads are still fetching pages that haven't returned yet?

“I got the BFS skeleton down pretty quickly, queue plus visited set, nothing too surprising.”

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Anthropic·Software Engineer·Onsite - Behavioral / Leadership

Jun 2026

Behavioral loop at Anthropic for a software engineer role, heavy on leadership principles and technical depth. The questions covered everything from architecture decisions to interpersonal conflict, and the AI product angle was clearly a filter for genuine interest rather than just a resume check.

Walk me through your career path, the reasons behind each transition, the impact you had, and how your scope grew over time.
Describe a project where you owned the frontend architecture end to end. What were the goals, the constraints, the trade-offs you made, and what did the outcomes actually look like?
Tell me about a situation where you pushed back on a decision to protect quality or the user experience, or had to navigate real ambiguity. What was the context and what happened?
Describe a conflict you had with a teammate or someone from another team. How did it play out and how did you resolve it?
Share a real failure or mistake you made professionally. What did you learn and what do you actually do differently now?
How do you show up on things like collaboration, taking ownership, keeping a high bar, and moving fast when it matters?
How do you keep your technical skills sharp, and how do you help the people around you grow?
Why do you want to work on a desktop AI product specifically, and what would you bring that someone else wouldn't?

“I'd rehearsed this plenty but still rambled a bit connecting the dots between jobs.”

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Anthropic·Software Engineer·Onsite - Behavioral / Leadership

Jun 2026

Culture round at Anthropic for a software engineer role. Felt less like a formal interview and more like a laid-back conversation, which honestly threw me off a bit since I'd prepped for the usual AI-safety values grilling.

Is there something you've kept doing consistently, even though it has no practical or utilitarian payoff for you?
Tell me about a time you had a disagreement with a coworker where you later realized you were the one who was wrong.

“This one surprised me.”

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Anthropic·Machine Learning Engineer·Technical Phone Screen

Jun 2026

Interviewed for an MLE role at Anthropic and got a file deduplication problem that started simple but turned into a pretty involved system design conversation about scaling strategies. The follow-up questions on streaming vs batch were where things got interesting.

Given a list of files, each with a path and contents, group together all files that share identical content so duplicates can be identified. Return every group that has two or more files.
How would you handle very large files in this deduplication approach, and what are the risks of hash collisions causing false positives?
How does your approach change if files are arriving as a continuous stream rather than a one-shot batch you process all at once?

“The base problem is straightforward enough, hash the contents and bucket by hash.”

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Anthropic·Software Engineer·Onsite - System Design / Architecture

Jun 2026

System design round at Anthropic for a software engineering role. The question was massive, basically a full ML platform design crammed into one session. Walked away feeling like I touched everything but went deep on nothing.

Design a low-latency ML inference API for real-time predictions. Cover SLOs, request/response schema, auth, rate limiting, and multitenancy. Then walk through the architecture: load balancing, stateless API tier, feature retrieval, model serving on CPU and GPU, batching, quantization, caching, and autoscaling. Also address model versioning, canary deployments and rollbacks, online A/B testing, observability (metrics, tracing, drift detection, data quality), cost controls, fallback behavior during partial outages, security, PII handling, regionalization, and disaster recovery.

“This question is basically a whole system design interview loop compressed into one prompt.”

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Anthropic·Software Engineer·Online Assessment (OA)

Jun 2026

Anthropic runs a CodeSignal-style multi-level coding assessment for their ChatBox Service role, and Level 3 is where things get genuinely tricky. The earlier levels are manageable but Level 3 piles on expiration logic, notification systems, and per-user filters all at once, which is a lot to hold in your head under a timer.

Design and implement a basic ChatBox Service with core messaging functionality (Level 1).
Extend the ChatBox Service with additional features building on your Level 1 implementation (Level 2).
Add advanced features to the ChatBox Service including message expiration, notification handling, and per-user message filters (Level 3).

“This part was fine.”

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Anthropic·Machine Learning Engineer·Technical Phone Screen

Jun 2026

Interviewed for an ML engineer role at Anthropic. The focus was squarely on AI safety and data privacy, which makes sense given the company, but I still felt underprepared for how deep they wanted to go.

How do you ensure user data remains safe and private when designing and building AI systems?

“I started talking about encryption and access controls and could tell pretty quickly that wasn't the angle they wanted.”

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Anthropic·Software Engineer·Onsite - Behavioral / Leadership

Jun 2026

Went through an execution and leadership round at Anthropic for an EM role. The focus was entirely on how you actually run a team, not just talk about it. Pretty intense if you're used to softer behavioral rounds.

How do you set direction for your team and make sure delivery actually follows from it?
Describe how you drive execution across teams that you don't directly manage.
Walk me through how you prioritize work when everything feels urgent.
How do you identify and mitigate risk before it becomes a problem for your team?
How do you hold the bar on quality without becoming a bottleneck?
How do you unblock people on your team while staying accountable for outcomes yourself?

“I rambled a bit connecting strategy to execution.”

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