Anthropic
AI safety and research company behind Claude, focusing on constitutional AI.
5 Rounds
~20 Days
Very Hard
The Interview Loop
Recruiter Screen (30 min)
Standard fit check, behavioral questions, and resume overview.
Technical Loop (3-4 Rounds)
Deep dive into domain knowledge, coding, and system design.
Interview Question Bank
Software Engineer
•
Behavioral
•
medium
Tell me about a time you had to balance shipping a feature quickly versus ensuring its safety, security, or reliability. How did you make the trade-off?
#AI Safety
#Decision Making
#Ethics
Software Engineer
•
Behavioral
•
medium
How do you handle situations where an ML researcher proposes an architecture or feature that is theoretically sound but practically unscalable or an engineering nightmare?
#Collaboration
#Conflict Resolution
#Cross-functional
Software Engineer
•
Behavioral
•
easy
Describe a time you had to dive into a complex codebase in a language or framework you were completely unfamiliar with to fix a critical bug.
#Learning
#Problem Solving
Software Engineer
•
Behavioral
•
medium
Tell me about a time you had to make a tradeoff between shipping a feature quickly and ensuring the system's safety or reliability. How did you navigate that decision?
#Tradeoffs
#Safety
#Communication
Software Engineer
•
Behavioral
•
easy
Why do you want to work at Anthropic specifically, as opposed to other major AI labs like OpenAI or Google DeepMind?
#Company Knowledge
#Motivation
#AI Safety
Software Engineer
•
Behavioral
•
medium
Describe a time you strongly disagreed with a technical direction proposed by a senior engineer or manager. How did you handle the situation and what was the outcome?
#Conflict Resolution
#Communication
#Technical Leadership
Software Engineer
•
Behavioral
•
easy
Tell me about a time you had to learn a complex new technology, framework, or domain on the fly to deliver a project. How did you approach the learning process?
#Adaptability
#Learning
#Problem Solving
Software Engineer
•
Behavioral
•
medium
Describe a project where you had to significantly optimize the performance of a system. What was the bottleneck, how did you identify it, and what was the solution?
#Performance
#Profiling
#Impact
Software Engineer
•
Behavioral
•
medium
Tell me about a time you discovered a critical bug or security vulnerability right before a major launch. What did you do?
#Crisis Management
#Integrity
#Communication
Software Engineer
•
Behavioral
•
medium
How do you handle ambiguity in product requirements, especially in a fast-moving and experimental field like generative AI?
#Ambiguity
#Product Sense
#Agile
Software Engineer
•
Behavioral
•
medium
Tell me about a time you had to balance shipping a feature quickly with ensuring the system remained safe, secure, or highly reliable.
#Safety
#Trade-offs
#Decision Making
Software Engineer
•
Behavioral
•
medium
Describe a situation where you strongly disagreed with a technical decision made by your team or manager. How did you handle it?
#Conflict Resolution
#Communication
#Teamwork
Software Engineer
•
Behavioral
•
easy
Why Anthropic? What specific aspects of our research, products, or mission around Constitutional AI and safety draw you here over other AI labs?
#Motivation
#Company Knowledge
#AI Safety
Software Engineer
•
Behavioral
•
medium
Tell me about a time you had to dive deep into a complex, unfamiliar codebase to fix a critical bug. What was your approach?
#Debugging
#Adaptability
#Problem Solving
Software Engineer
•
Behavioral
•
medium
How do you prioritize your engineering tasks when everything seems urgent, and requirements are highly ambiguous?
#Prioritization
#Ambiguity
#Time Management
Software Engineer
•
Behavioral
•
hard
Describe a time you identified a critical security, privacy, or safety flaw in a system. How did you discover it, and how did you drive the remediation?
#Security
#Proactivity
#Impact
Software Engineer
•
Behavioral
•
hard
Tell me about the most complex debugging experience of your career. What made it difficult, and what did you learn?
#Debugging
#Resilience
#Technical Depth
Software Engineer
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Coding
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medium
Implement a token bucket rate limiter for an API endpoint. Extend it to handle distributed rate limiting across multiple servers.
#Concurrency
#API Design
#Distributed Systems
Software Engineer
•
Coding
•
medium
Write a function to parse a raw stream of Server-Sent Events (SSE) and yield complete JSON objects. The network can chunk the data at arbitrary byte boundaries.
#String Manipulation
#Networking
#Streaming
Software Engineer
•
Coding
•
medium
Implement a text chunking algorithm that takes a large document and splits it into chunks of maximum N tokens, ensuring that chunks only break on sentence boundaries.
#NLP
#String Manipulation
#Edge Cases
Software Engineer
•
Coding
•
hard
Implement a basic version of the scaled dot-product attention mechanism using pure NumPy. Include an optional causal mask.
#Linear Algebra
#NumPy
#Transformers
Software Engineer
•
Coding
•
medium
Implement an LRU (Least Recently Used) cache. Once completed, discuss how you would modify it to support an LFU (Least Frequently Used) eviction policy for LLM prompt caching.
#Caching
#Hash Map
#Linked List
Software Engineer
•
Coding
•
hard
Write a concurrent web scraper that fetches a list of URLs. It must respect robots.txt, enforce a maximum of N concurrent requests per domain, and handle retries with exponential backoff.
#Concurrency
#Web Scraping
#Error Handling
Software Engineer
•
Coding
•
hard
Implement a basic Byte Pair Encoding (BPE) tokenizer. Given a string of text and a target vocabulary size, write a function to iteratively merge the most frequent adjacent pairs of characters or subwords.
#Strings
#Hash Maps
#Priority Queue
#LLM Fundamentals
Software Engineer
•
Coding
•
hard
Design a streaming JSON parser. In our LLM inference API, Claude streams responses token by token. Sometimes the output is a JSON object, but the client receives it in incomplete chunks. Write a function that takes a stream of characters and yields the deepest valid JSON structure possible at any given moment.
#Parsing
#State Machines
#Trees
#Streaming
Software Engineer
•
Coding
•
medium
Write a rate limiter for an API. The rate limiter should support different limits based on the user's tier (e.g., free vs. paid) and should be based on the number of tokens generated, not just the number of requests.
#Concurrency
#Token Bucket
#Object-Oriented Design
Software Engineer
•
Coding
•
medium
Implement an asynchronous task queue in Python using asyncio. The queue should support task priorities, concurrent worker limits, and graceful shutdown.
#Python
#Asyncio
#Concurrency
#Heaps
Software Engineer
•
Coding
•
medium
Write a function to compute the cosine similarity between two dense vectors. Then, optimize it to find the top K most similar vectors from a massive list of vectors (e.g., 1 million) as quickly as possible.
#Math
#Arrays
#Heaps
#Optimization
Software Engineer
•
Coding
•
medium
Implement an LRU Cache with a Time-To-Live (TTL) feature. If an item is accessed after its TTL has expired, it should be treated as a cache miss and removed.
#Linked Lists
#Hash Maps
#Caching
Software Engineer
•
Coding
•
easy
Given a list of conversation logs with start and end timestamps, write a function to merge overlapping intervals to find the total continuous time a user spent interacting with the model.
#Sorting
#Arrays
#Intervals
Software Engineer
•
Coding
•
hard
Implement a text diffing algorithm. Given two strings (an original prompt and an edited prompt), return a list of operations (Insert, Delete, Keep) to transform the original into the edited version.
#Dynamic Programming
#Strings
Software Engineer
•
Coding
•
medium
Write a function that takes a long string of text and a maximum line length, and returns the text word-wrapped. Words longer than the line length should be broken with a hyphen.
#Strings
#Formatting
#Edge Cases
Software Engineer
•
Coding
•
medium
Implement a Trie (Prefix Tree) to support fast autocomplete suggestions. Include a method to insert words with a frequency score, and a method to retrieve the top 3 most frequent completions for a given prefix.
#Trees
#Trie
#Design
#Sorting
Software Engineer
•
Coding
•
easy
Write a retry decorator in Python that implements exponential backoff with jitter. It should take parameters for maximum retries, base delay, and exceptions to catch.
#Python
#Decorators
#Networking
#Math
Software Engineer
•
Coding
•
medium
Given a Directed Acyclic Graph (DAG) representing a chain of LLM prompts where some prompts depend on the outputs of others, write an execution engine that runs the prompts in the correct order, maximizing concurrency.
#Graphs
#Topological Sort
#Concurrency
#Asyncio
Software Engineer
•
Coding
•
easy
Implement a sliding window algorithm to manage an LLM's context window. Given an array of text chunks with token counts and a maximum token limit, find the contiguous subarray of chunks that maximizes the token count without exceeding the limit.
#Sliding Window
#Arrays
#Two Pointers
Software Engineer
•
Coding
•
medium
Write a program to parse a massive log file (e.g., 50GB) to find the top 10 most frequent IP addresses. You have limited RAM (e.g., 1GB).
#File I/O
#Hashing
#Heaps
#Memory Management
Software Engineer
•
Coding
•
medium
Implement a token bucket rate limiter to throttle incoming API requests based on a user's tier. It should handle concurrent requests safely.
#Concurrency
#Data Structures
#API Design
Software Engineer
•
Coding
•
hard
Write a simplified Byte Pair Encoding (BPE) tokenizer. Given a corpus of text and a target vocabulary size, implement the training loop to find the most frequent adjacent character pairs and merge them.
#String Manipulation
#Hash Maps
#Heaps
Software Engineer
•
Coding
•
medium
Implement a parser for Server-Sent Events (SSE) that consumes a raw byte stream from an LLM and yields complete JSON objects, handling network interruptions and fragmented chunks.
#I/O Streaming
#State Machines
#String Parsing
Software Engineer
•
Coding
•
hard
Write an asynchronous task batcher. It should accept individual requests, wait for either a maximum batch size or a maximum time window, and then process the batch together.
#Asynchronous Programming
#Concurrency
#System Timers
Software Engineer
•
Coding
•
medium
Implement a Trie-based caching mechanism to store and retrieve LLM prompt prefixes, returning the longest matching cached prefix for a new prompt.
#Trees
#Caching
#String Matching
Software Engineer
•
Coding
•
medium
Given a massive log file of API requests, write a script to find the top K users who experienced the highest error rates in a specific 5-minute sliding window.
#Sliding Window
#Heaps
#Log Parsing
Software Engineer
•
Coding
•
hard
Implement a basic Key-Value (KV) cache data structure used in transformer attention mechanisms. It needs to support appending new tokens, evicting the oldest tokens when a max length is reached, and fast retrieval.
#Data Structures
#Linked Lists
#Hash Maps
Software Engineer
•
Coding
•
medium
Given a set of Constitutional AI rules represented as a directed acyclic graph (where edges represent dependencies between rules), write a function to determine a valid execution order.
#Graphs
#Topological Sort
#DFS/BFS
Software Engineer
•
Coding
•
medium
Given a string of text and a list of overlapping highlight annotations (start_index, end_index, label), write a function to merge overlapping intervals and return a flattened list of text segments.
#Intervals
#Sorting
#Arrays
Software Engineer
•
Coding
•
easy
Write a function to manage a sliding context window for an LLM. Given a list of messages and a maximum token limit, return the optimal subset of messages that fits, ensuring the system prompt is always included.
#Arrays
#Greedy Algorithms
#Logic
Software Engineer
•
Coding
•
medium
Implement a thread-safe asynchronous queue from scratch using basic concurrency primitives (mutexes, condition variables).
#Concurrency
#Data Structures
#Synchronization
Software Engineer
•
Coding
•
hard
Write a custom JSON parser that can recover from common malformed outputs generated by LLMs (e.g., missing closing brackets, trailing commas, unescaped quotes).
#Parsing
#String Manipulation
#Heuristics
Software Engineer
•
Coding
•
hard
Given an array of integers representing the execution times of tasks and an integer K representing the number of available workers, write a function to assign tasks to workers to minimize the maximum time spent by any worker.
#Binary Search
#Greedy Algorithms
#Optimization
Software Engineer
•
System Design
•
hard
Design a high-throughput LLM inference service. How would you handle continuous batching, KV cache memory management, and streaming responses back to the client?
#ML Infrastructure
#Distributed Systems
#GPU Memory Management
Software Engineer
•
System Design
•
hard
Design a distributed data pipeline to process petabytes of raw web text for LLM pre-training. It needs to filter out PII, deduplicate documents, and tokenize the text.
#Big Data
#Data Pipelines
#MapReduce
Software Engineer
•
System Design
•
hard
Design a system to monitor, detect, and block prompt injection attacks in real-time across millions of API requests per minute.
#Security
#Stream Processing
#Low Latency
Software Engineer
•
System Design
•
medium
Design a scalable model evaluation framework. Researchers need to run thousands of benchmark tests (MMLU, HumanEval) against new model checkpoints daily.
#Task Queues
#Scalability
#CI/CD
Software Engineer
•
System Design
•
medium
Design a system for securely storing and querying user conversation history with Claude. The system must ensure strict privacy, support fast retrieval for context windows, and comply with data deletion requests.
#Databases
#Privacy
#Security
Software Engineer
•
System Design
•
medium
Design the backend architecture for Claude.ai's chat interface. How would you handle conversation history, branching conversations (editing a previous prompt), and streaming responses to the frontend?
#API Design
#WebSockets/SSE
#Database Schema
#State Management
Software Engineer
•
System Design
•
hard
Design a distributed web crawler tailored for gathering LLM training data. How do you handle deduplication at a massive scale, respect robots.txt, and prioritize high-quality domains?
#Distributed Systems
#Message Queues
#Hashing
#Data Pipelines
Software Engineer
•
System Design
•
hard
Design a system to evaluate LLM outputs for safety and alignment (Constitutional AI pipeline). How would you architect a high-throughput asynchronous pipeline that runs multiple smaller classifier models on Claude's outputs before returning them to the user?
#Microservices
#Stream Processing
#Latency Optimization
#Machine Learning Infrastructure
Software Engineer
•
System Design
•
hard
Design a multi-tenant Retrieval-Augmented Generation (RAG) system for enterprise clients. How do you ensure data isolation, scalable vector search, and low-latency retrieval?
#Vector Databases
#Security
#Multi-tenancy
#Search
Software Engineer
•
System Design
•
medium
Design an asynchronous batch processing system for offline LLM generation tasks (e.g., summarizing millions of documents). How do you handle retries, partial failures, and dynamic scaling of GPU workers?
#Batch Processing
#Message Queues
#Fault Tolerance
#GPU Infrastructure
Software Engineer
•
System Design
•
medium
Design a telemetry and logging system for tracking model hallucinations or safety violations in production. The system must handle millions of events per minute without impacting the critical path of the inference API.
#Logging
#Asynchronous Processing
#Big Data
#Observability
Software Engineer
•
System Design
•
hard
Design a distributed Key-Value store specifically optimized for caching LLM prompt embeddings. It needs to support high read throughput and fast eviction.
#Distributed Systems
#Caching
#Consistent Hashing
#Replication
Software Engineer
•
System Design
•
hard
Design a global API rate limiting system for Anthropic's enterprise customers. It must be highly available, have minimal latency impact, and strictly enforce limits across multiple geographic regions.
#Distributed Systems
#Redis
#Rate Limiting
#Consistency
Software Engineer
•
System Design
•
hard
Design a streaming inference API architecture. How do you route incoming requests to available GPU workers, handle worker failures mid-stream, and stream the generated tokens back to the client?
#Load Balancing
#Streaming
#Fault Tolerance
#GPU Infrastructure
Software Engineer
•
System Design
•
hard
Design a low-latency inference API for a Large Language Model like Claude. How do you handle request batching, streaming responses, and model weight distribution across GPUs?
#Distributed Systems
#Machine Learning Infrastructure
#Latency Optimization
Software Engineer
•
System Design
•
hard
Design a distributed data processing pipeline to ingest, deduplicate, and filter petabytes of web scraping data for LLM pre-training.
#Data Pipelines
#MapReduce
#Storage
Software Engineer
•
System Design
•
medium
Design a system to detect and block prompt injection attacks in real-time across millions of API requests per day.
#Security
#Stream Processing
#Microservices
Software Engineer
•
System Design
•
medium
Design a scalable chat history storage system for a consumer-facing LLM application (like Claude.ai) that allows fast retrieval of recent messages and efficient storage of long contexts.
#Databases
#Caching
#Data Modeling
Software Engineer
•
System Design
•
hard
Design a distributed caching layer for LLM responses to serve identical queries instantly. How do you handle cache invalidation, semantic similarity, and high read/write throughput?
#Caching
#Vector Databases
#Distributed Systems
Software Engineer
•
System Design
•
hard
Design a telemetry and monitoring system for a cluster of 10,000 GPUs. It needs to detect hardware failures, thermal throttling, and network bottlenecks in real-time.
#Monitoring
#Distributed Systems
#Hardware Infrastructure
Software Engineer
•
System Design
•
medium
Design an A/B testing framework specifically for evaluating new versions of an LLM. How do you route traffic, measure qualitative metrics (like helpfulness), and ensure statistical significance?
#A/B Testing
#Data Engineering
#Analytics
Software Engineer
•
System Design
•
medium
Design an asynchronous batch processing system for offline LLM inference (e.g., processing millions of documents for embeddings).
#Batch Processing
#Message Queues
#Scalability
Software Engineer
•
System Design
•
hard
Design a real-time collaborative prompt engineering tool (similar to Google Docs for prompts) where multiple users can edit, test, and version-control prompts simultaneously.
#Real-time Systems
#Operational Transformation
#WebSockets
Software Engineer
•
System Design
•
medium
Design a rate-limiting service that supports multiple dimensions: per user, per organization, and per IP address, with different limits for each.
#API Design
#Redis
#Scalability
Software Engineer
•
Technical
•
hard
Here is an asynchronous Python script used for concurrent API scraping that is randomly deadlocking. Walk me through how you would debug and fix it.
#Python
#Asyncio
#Debugging
Software Engineer
•
Technical
•
medium
How would you debug a severe memory leak in a Python application that processes large volumes of text data for model training?
#Python
#Memory Management
#Profiling
#Garbage Collection
Software Engineer
•
Technical
•
hard
Explain how Key-Value (KV) caching works during transformer inference. Why is it necessary, and what are the memory implications for long context windows?
#Transformers
#Inference
#Memory Management
#LLM Architecture
Software Engineer
•
Technical
•
medium
How do you handle backpressure in a streaming data pipeline? Imagine a scenario where our inference engines are producing tokens faster than the client's network connection can receive them.
#Networking
#Streaming
#TCP/IP
#Concurrency
Software Engineer
•
Technical
•
hard
How would you optimize PyTorch dataloaders for training a model on a massive, multi-terabyte text dataset stored in AWS S3?
#PyTorch
#Data Pipelines
#Cloud Storage
#Performance Optimization
Software Engineer
•
Technical
•
medium
Design the database schema for a chat application like Claude. It must support users, chat sessions, individual messages, and the ability to 'edit and retry' a message, which creates a new branch of the conversation.
#SQL
#Database Schema
#Trees
#Data Modeling
Software Engineer
•
Technical
•
medium
Explain how you would optimize a Python microservice that has become CPU-bound due to heavy text processing and regex matching.
#Python
#GIL
#Profiling
Software Engineer
•
Technical
•
hard
How does memory fragmentation affect long-running processes in languages like Rust or C++, and what strategies would you use to mitigate it in a high-throughput API server?
#Memory Management
#Rust
#C++
Software Engineer
•
Technical
•
medium
Explain the trade-offs between using gRPC versus REST for internal microservices communication in a high-throughput environment.
#Networking
#Protocols
#Microservices
Software Engineer
•
Technical
•
medium
How would you implement distributed locking for a shared resource in an AWS environment to ensure only one worker processes a specific task at a time?
#AWS
#Concurrency
#Locks
Software Engineer
•
Technical
•
medium
Discuss the challenges of managing state in a WebSocket-based streaming application. How do you handle load balancing, connection drops, and state recovery?
#WebSockets
#Networking
#State Management
Difficulty Radar
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Senior EngineerFocuses on core competencies, system constraints, and clear communication.
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