Anthropic interview notes, page 4 of 32

Mid-sized

Most of these Anthropic write-ups come from Software Engineers (277), then Machine Learning Engineers (31) and Product Managers (10). The most reported rounds are the technical phone screen (129), the system design round (86), the behavioral / leadership round (45) and the hiring manager screen (17).

319 interview notes · updated Sep 2026

Anthropic·Software Engineer·Onsite - Behavioral / Leadership

Apr 2026

Behavioral round at Anthropic for a software engineering role. Two questions, both with follow-up twists that pushed past any rehearsed answer I had ready. The interviewer wasn't technical, which changed how I had to frame everything.

What kind of work do you least enjoy, and then convince me to do that same work when the team needs it, assuming I dislike it just as much as you do.
Tell me about something you did that you later realized was ethically or morally wrong. What happened, how did you address it, and what actually changed in how you operate afterward?

“Two questions hiding inside one.”

View Post

Anthropic·Software Engineer·Onsite - System Design / Architecture

Apr 2026

System design round at Anthropic for a software engineer role, focused entirely on batch inference for large ML models. Pretty deep dive, they clearly wanted to see if you'd thought about GPU efficiency and failure recovery at scale, not just the happy path.

Design a batch inference system for a large language model that processes millions of offline requests as efficiently as possible, including job submission, status tracking, output persistence, and retry logic for failed items.
How would you maximize GPU utilization across a large batch workload with variable-length inputs, including your approach to batching strategy and memory management?
How would you handle multi-tenant scheduling with priority levels, quotas, and potential preemption across competing batch jobs?
What observability would you build into this system, and what metrics matter most for understanding whether the system is healthy and cost-efficient?

“This is a beast of a question.”

View Post

Anthropic·Software Engineer·Technical Phone Screen

Apr 2026

Interviewed for a software engineering role at Anthropic. The technical portion involved an LRU cache problem and I ran out of time partly because of CoderPad setup issues. Rejection came Friday after a Monday interview.

Debug and extend an LRU cache implementation.

“Lost a chunk of time just figuring out the CoderPad file path situation, which was embarrassing.”

View Post

Anthropic·Software Engineer·Onsite - Behavioral / Leadership

Apr 2026

Anthropic's culture round for the EM role was less about what you've built and more about how you think about risk and ego. Three prompts, all circling the same theme: do you know when to pump the brakes on yourself?

Tell me about a time you walked away from a technically impressive solution because the risk wasn't worth it.
How do you handle disagreements with a strong-willed researcher or PM who pushes back hard on your technical direction?
Walk me through how you make decisions when you're operating in a system with a lot of unknowns and incomplete information.

“This one tripped me up a little because my first instinct was to pick something where I looked decisive and smart.”

View Post

Anthropic·Software Engineer·Onsite - System Design / Architecture

Apr 2026

System design round at Anthropic for a software engineer role. The web crawler question sounds deceptively straightforward but there's a lot of surface area once you start pulling on the concurrency and politeness threads.

Design a web crawler that starts from a seed URL, fetches pages, extracts hyperlinks, and recursively crawls them without revisiting the same URL twice.

“I started with BFS because it felt safer to defend and the interviewer seemed fine with that.”

View Post

Anthropic·Software Engineer·Technical Phone Screen

Apr 2026

Anthropic coding screen for a software engineer role, one question the whole time: build a tokenizer from scratch. Felt more like a systems thinking exercise than a pure coding grind.

Implement a tokenizer from scratch: given a vocabulary (a set of strings) and an input text, segment the text using longest-match-first. Handle characters not in the vocabulary without crashing or looping forever. Then discuss time complexity and how a trie would change things.

“My first instinct was to reach for a trie immediately, which I think actually hurt me because I spent a minute talking about it before writing anything.”

View Post

Anthropic·Software Engineer·Onsite - Coding / Algorithms

Apr 2026

Coding round at Anthropic for a SWE role. One problem, real file system access, and you could look up syntax which was a nice change from the usual "pretend you're in a vacuum" setup.

Write a program that scans a file system and identifies duplicate files, handling real files, extensions, and actual file reading.

“The live file system access was something I didn't expect.”

View Post

Anthropic·Machine Learning Engineer·Recruiter / HR Screen

Apr 2026

Behavioral screen for an ML Engineer role at Anthropic. Pretty standard HR round, three questions, nothing too surprising but the values question tripped me up more than I expected.

Why do you want to join Anthropic?
Which of Anthropic's values resonates most with you, and why?
What's your greatest strength, and how has it shown up in your work?

“I had an answer prepped but it came out a bit generic.”

View Post

Anthropic·Software Engineer·Technical Phone Screen

Apr 2026

Anthropic coding round focused on extending a key-value store with backup and restore functionality, including some tricky TTL pausing logic that took me a while to think through clearly.

You have an in-memory key-value store. Extend it to support backup(timestamp) and restore(at_timestamp), where backup pauses TTL countdowns and restore resumes remaining TTL for each key from the most recent snapshot at or before the given timestamp.

“The core data structure part was fine but the TTL semantics tripped me up.”

View Post

Anthropic·Software Engineer·Onsite - System Design / Architecture

Apr 2026

Anthropic system design round for a software engineering role, focused entirely on building a web crawler from scratch. The question had a lot of moving parts and I felt like I was playing catch-up the whole time.

Design and implement a basic web crawler that fetches pages concurrently using a thread executor. Walk through your data structures for the frontier and visited set, how you handle duplicate URLs, and how you'd test and monitor the whole thing.

“This question ate me alive a little.”

View Post