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Anthropic·Software Engineer·Online Assessment (OA)·Intermediate

Intermediate
Apr 2026Remote

Summary

Anthropic coding assessment for what looks like a backend or software engineering role. Level 2 of a multi-level CodeSignal-style problem building a ChatBox Service, extending a Level 1 API with things like direct messages, channel membership, and message history. Pretty involved for an OA.

Questions Asked (1)

Q1

Extend a Level 1 ChatBox Service API to support additional operations including direct messaging, channel membership management, and querying message history.

API & IntegrationsSystem DesignData Modeling
Author's notes

This is a build-on-top problem, so if your Level 1 was messy you'll feel it immediately.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the existing Level 1 API and the new requirements, then design the API endpoints and data models for direct messaging, channel membership, and message history. Focus on consistency, scalability, and security, and discuss trade-offs in your design choices.

Pro tip: Demonstrate awareness of real-world constraints like rate limiting, pagination, and idempotency, and tie your design to Anthropic's focus on safety and reliability.

1. Clarify Requirements and Scope

Ask questions to understand the existing Level 1 API, expected scale, and specific needs for direct messaging, membership, and history. Confirm non-functional requirements like latency, consistency, and security.

2. Design Data Models

Define schemas for users, channels, messages, and memberships, considering relationships and indexing for efficient queries. Discuss trade-offs between normalization and denormalization for read/write performance.

3. Define API Endpoints

Outline RESTful endpoints for sending direct messages, managing channel members (add/remove/list), and retrieving message history with pagination. Specify request/response formats and status codes.

4. Address Scalability and Reliability

Discuss strategies for handling high throughput, such as sharding, caching, and asynchronous processing. Include error handling, retries, and idempotency for critical operations.

5. Consider Security and Privacy

Explain authentication, authorization, and data privacy measures, such as access controls for direct messages and channel membership. Mention encryption and audit logging.

Key Points to Mention

  • RESTful API design principles and consistent naming conventions
  • Data modeling for messages, channels, and memberships with appropriate indexes
  • Pagination strategies (e.g., cursor-based) for message history
  • Idempotency and rate limiting for message sending
  • Authorization checks for direct messages and channel operations
  • Scalability considerations like sharding, caching, and asynchronous processing

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