← Anthropic Interview Insights

Anthropic·Software Engineer·Onsite - System Design / Architecture·Senior

Senior
Jun 2026

Summary

Interviewed for a SWE role at Anthropic and got a system design question focused on batching infrastructure for LLM inference. Pretty domain-specific stuff, not your typical distributed systems question.

Questions Asked (1)

Q1

Design an end-to-end batching system for LLM queries, including an API that efficiently groups and processes sampling requests at scale.

System DesignAPI & IntegrationsTechnical Trade-offs
Author's notes

This one took me a minute to even figure out what angle they wanted.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and constraints (latency SLOs, throughput, cost, model types) and then present a high-level architecture that separates the API layer from the batching scheduler and inference workers. Walk through the request lifecycle, batching strategies (time-based, size-based, continuous batching), and trade-offs around latency vs. throughput, then dive into scaling, fault tolerance, and monitoring.

Pro tip: Emphasize that batching is not just about grouping requests but also about smart scheduling: use priority queues and deadline-aware batching to meet SLAs, and consider prefill/decode separation for LLMs to maximize GPU utilization.

1. Clarify Requirements and Constraints

Ask about expected QPS, latency SLOs, model sizes, cost constraints, and whether requests are interactive or offline. This shapes the batching strategy and infrastructure choices.

2. Design the API Layer

Define a stateless, scalable API (e.g., REST/gRPC) that accepts sampling requests, validates them, and enqueues them into a distributed queue. Include authentication, rate limiting, and request deduplication.

3. Design the Batching Scheduler

Implement a scheduler that groups requests based on time windows, batch size limits, and priority/deadlines. Use a distributed queue (e.g., Kafka, Redis) and a batching service that forms batches and dispatches them to inference workers.

4. Design Inference Workers and Model Execution

Workers pull batches, run them on GPUs with optimized inference (e.g., TensorRT, vLLM), and return results. Consider continuous batching, prefill/decode separation, and dynamic batching to maximize throughput.

5. Address Scaling, Fault Tolerance, and Monitoring

Scale horizontally, handle failures with retries and dead-letter queues, and monitor key metrics (latency, batch size, GPU utilization, error rates). Discuss autoscaling and cost optimization.

Key Points to Mention

  • Batching strategies: time-based, size-based, and continuous batching for LLMs
  • Trade-offs between latency and throughput, and how to tune batch size and timeout
  • Use of priority queues and deadline-aware scheduling to meet SLAs
  • Distributed queueing and backpressure to handle load spikes
  • GPU utilization optimizations: prefill/decode separation, paged attention, dynamic batching
  • Fault tolerance: retries, idempotency, dead-letter queues, and graceful degradation

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.