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Openai·Software Engineer·Technical Phone Screen·Intermediate

IntermediatePrefer not to say
Jun 2026Remote

Summary

Interviewed for a SWE role at OpenAI and got a chatbot routing problem. Not the typical leetcode grind, more of a design-meets-implementation hybrid that felt closer to real product work than I expected.

Questions Asked (1)

Q1

Design and implement a message router for a chat channel with multiple bots (e.g. an away bot, a taco bot, a meeting bot), where each incoming message may trigger zero or more bots based on their individual rules, and responses must be returned in a specified priority order.

System DesignAlgorithms & Data StructuresAPI & Integrations
Author's notes

The problem sounds manageable until you realize the bot trigger rules aren't given upfront.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and constraints, then propose a modular architecture with a central router that evaluates each bot's rules against the incoming message. Discuss data structures for efficient rule evaluation and priority ordering, and outline how to handle asynchronous bot responses while maintaining order.

Pro tip: Emphasize extensibility and testability: design the router so new bots can be added without modifying core logic, and mention how you'd unit test each bot's rules and the priority ordering.

1. Clarify Requirements

Ask about expected message volume, latency requirements, bot rule complexity, and whether bot responses are synchronous or asynchronous. Confirm the priority order specification and failure handling.

2. Design Core Components

Define interfaces for Bot (with a method to evaluate a message and generate a response) and Router (which manages bots and routes messages). Consider a registry for bots and a priority queue for responses.

3. Implement Routing Logic

For each incoming message, iterate through bots (or use an index for efficiency), collect responses from bots whose rules match, then sort responses by priority before returning.

4. Handle Asynchrony and Ordering

If bots process asynchronously, use promises/futures and await all responses, then sort by priority. Ensure that slow bots don't block others unnecessarily, but still respect priority in final output.

5. Discuss Extensibility and Testing

Explain how to add new bots without changing router code (e.g., plugin architecture). Outline unit tests for rule matching, priority ordering, and edge cases like no matching bots or bot failures.

Key Points to Mention

  • Bot interface with methods like `shouldRespond(message)` and `generateResponse(message)`
  • Priority queue or sorting mechanism for ordering responses
  • Efficient rule evaluation (e.g., indexing rules, early exit if no bots match)
  • Asynchronous processing with Promise.all or similar, and handling timeouts/failures
  • Extensibility via dependency injection or plugin registration
  • Testing strategy: unit tests for bots, integration tests for router

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