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

Senior
Apr 2026

Summary

Did a system design round at OpenAI for a software engineer role, got asked to design a video scheduling service along the lines of Sora. Pretty intense scope for one session.

Questions Asked (1)

Q1

Design a video scheduling service similar to Sora. Walk through the architecture, key components, and how you'd handle scale.

System DesignTechnical Trade-offsData Modeling
Author's notes

This one is deceptively wide.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and scale (e.g., number of users, videos per day, latency expectations). Then propose a high-level architecture with key components like API gateway, job queue, scheduler, workers, and storage, and discuss trade-offs for scaling each component. Finally, dive into data modeling and how you'd handle bottlenecks like GPU availability and cost.

Pro tip: Emphasize the unique challenges of video generation (long-running GPU tasks, large file storage) and how you'd design for fault tolerance and cost efficiency, showing you understand OpenAI's specific domain.

1. Clarify Requirements and Scale

Ask questions to understand expected scale (e.g., daily active users, videos per day), latency requirements, and budget constraints. This ensures your design is appropriately sized.

2. High-Level Architecture

Sketch the main components: client, API gateway, job queue, scheduler, worker pool (with GPUs), storage (for input/output), and database. Explain the flow from request to video delivery.

3. Deep Dive into Key Components

Discuss the scheduler's role in managing GPU resources, the queue for decoupling, and how workers process jobs. Mention trade-offs like synchronous vs. asynchronous processing.

4. Scaling and Reliability

Explain how to scale each component (e.g., horizontal scaling of workers, sharding the database) and ensure reliability (retries, dead-letter queues, monitoring).

5. Data Modeling and Storage

Describe the data schema for jobs, users, and videos, and choose appropriate storage solutions (e.g., object storage for videos, relational DB for metadata).

Key Points to Mention

  • Asynchronous job processing with a message queue (e.g., Kafka, RabbitMQ) to handle long-running video generation tasks.
  • GPU resource management and scheduling (e.g., Kubernetes with GPU nodes, custom scheduler) to optimize utilization and cost.
  • Storage strategies: object storage (S3) for videos, CDN for delivery, and database for metadata.
  • Scalability patterns: horizontal scaling, sharding, caching, and rate limiting.
  • Fault tolerance: retries, idempotency, dead-letter queues, and monitoring/alerting.
  • Cost optimization: spot instances, auto-scaling, and tiered storage.

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