Anthropic Interview Questions — Page 12

Anthropic·Software Engineer·Technical Phone Screen

May 2026

Anthropic SWE interview with an iterative debugging exercise on a tokenizer. You fix one bug, they immediately ask what breaks next. Kept me on my toes the whole time.

A tokenizer implementation has already had one bug fixed. Run it again, find the next defect, explain how the first fix exposed it, show what input now fails, and describe the correct behavior.

“This one tripped me up more than I expected.”

View Post

Anthropic·Software Engineer·Onsite - Behavioral / Leadership

May 2026

Culture-fit conversation at Anthropic for a software engineering role, focused almost entirely on how you think about AI as a practitioner. Less about past projects, more about whether you actually have opinions on the field.

What recent AI developments excite or concern you, and why?
How do you see AI changing your day-to-day work and the products you build over the next few years?
Where do you think AI is currently overhyped versus underrated?
How do you stay current with AI research and how have you applied recent advances in your own work?

“This is the kind of question that sounds easy until you're actually in it and realize you've been nodding along to AI news for months without forming a real opinion.”

View Post

Anthropic·Machine Learning Engineer·Onsite - System Design / Architecture

May 2026

A system design round at Anthropic for an MLE role. The question was essentially one giant prompt covering every corner of distributed inference routing you could think of, and they expected you to hold it all together coherently for the duration of the interview.

Design a routing layer between an API service and heterogeneous inference backends (GPU and CPU) that supports traffic prioritization across tenants and request classes, dynamic batching, a query result cache, and credit-based fairness similar to GPU credits. Walk through the end-to-end architecture, request lifecycle, APIs, data structures, and the algorithms you'd use for prioritization, batching, and cache admission and eviction.
How would you handle SLAs, backpressure, hot keys in the cache, heterogeneous model sizes, multi-tenant isolation, and failure scenarios like node loss, stragglers, and retries within this routing system?
Describe your capacity planning and scaling strategy for this system, and what monitoring and alerting signals you would instrument.
Walk through the trade-offs between latency, throughput, and cost in this design, and how you would run experiments to tune the batching and caching parameters.

“This is the kind of question where the scope alone can paralyze you.”

View Post

Anthropic·Software Engineer·Onsite - System Design / Architecture

May 2026

Interviewed for a software engineering role at Anthropic and got a system design question about distributing model weights. Niche enough that I wasn't fully prepared for it.

Design a system for distributing large ML model weights to inference servers at scale.

“This one tripped me up more than I expected.”

View Post

Anthropic·Software Engineer·Onsite - System Design / Architecture

May 2026

System design round at Anthropic for a software engineering role, focused entirely on designing a scalable one-to-one chat system. Pretty deep dive, they wanted assumptions upfront and then pushed into the weeds on Kafka internals and tradeoffs.

Design a scalable one-to-one chat system. Before diving in, state your assumptions about scale, latency, and reliability requirements.
Walk through the core user flows for sending and receiving a message, including message persistence and retrieval.
How would your system handle message delivery when the recipient is online versus when they're offline?
How does the system detect whether a user is currently online or offline?
How do you store and manage client sessions and WebSocket connections across multiple servers?
How would you handle message ordering, retries, deduplication, and delivery acknowledgements?
What are the tradeoffs between using Kafka and Redis for the messaging pipeline in this design?
Explain the internal Kafka concepts that are relevant to this system: partitions, message ordering, offsets, and consumer groups.

“The scope was deliberately narrow, no group chat, no threads, just direct messaging.”

View Post

Anthropic·Software Engineer·Technical Phone Screen

May 2026

Technical screen at Anthropic for a software engineering role, focused entirely on low-level systems optimization. One question, very deep, and they clearly wanted more than surface-level answers about bit tricks.

For a compute-intensive inner loop that operates on integers, walk through bit-level optimizations you'd apply to reduce branching and memory traffic. Cover things like population count, fast modulo using bitmasks, branchless conditional updates, and alignment checks. Show code, explain why it's correct, and discuss the microarchitectural effects.

“This one sprawled in a way I didn't expect.”

View Post

Anthropic·Machine Learning Engineer·Onsite - System Design / Architecture

May 2026

System design round at Anthropic for an ML Engineer role, focused entirely on a data batching component and what breaks when you actually ship it. The question started reasonable and then kept going into territory I hadn't fully thought through.

You're given a DataBatcher that pulls from multiple datasets with weighted sampling and supports save/resume via an offset. What production issues would you need to handle before deploying this in a real ML training pipeline?

“I started with the obvious stuff, prefetching, per-dataset buffers, backpressure when the consumer lags.”

View Post

Anthropic·Software Engineer·Onsite - Behavioral / Leadership

May 2026

Behavioral round at Anthropic for a SWE role. Just the one question from what I can tell, but it's the kind that can spiral if you're not careful.

Describe a situation where you encountered a moral or ethical dilemma in a professional setting.

“Fitting question for Anthropic of all places.”

View Post

Anthropic·Software Engineer·Technical Phone Screen

May 2026

Interviewed for a software engineering role at Anthropic and got a coding problem centered on a task management system. The core challenge was designing efficient time-range queries, which sounds straightforward until you're staring at a whiteboard thinking about binary search edge cases.

You have a task management system where each task has an id, status, created_time, and updated_time, stored in an in-memory map. Design a way to efficiently query all tasks created or updated within a given time range [start, end], without re-scanning every task on each query.
What is the time complexity of each operation in your solution, including inserting a new task event and querying a time range?

“I jumped straight to 'just iterate the map and filter' and they let me finish before asking what happens if you call this a thousand times.”

View Post

Anthropic·Software Engineer·Onsite - Behavioral / Leadership

May 2026

Culture-fit round at Anthropic for a software engineer role. Two questions, both pretty philosophical, neither had a clean right answer which made it weirdly hard to prep for.

Tell me about a time you did something altruistic that wasn't in your own self-interest. What motivated you, what did you do, and what was the outcome?
A lot of people think AI development is genuinely dangerous. Why do you still want to work in this space, and how do you personally think about managing those risks?

“I had a story ready but partway through telling it I started second-guessing whether it actually qualified as altruistic or if I just looked good from it anyway.”

View Post