Engineering Lab
System Design Simulator
Pick components and architecture decisions, then score scalability, reliability, performance, cost, and complexity.
Al Beltran Engineering Lab
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How the challenge works
- Select the components you would actually ship, then answer the decision prompts.
- The score is a rubric, not a production audit. Missing a required piece hurts more than adding a nice-to-have.
Key concepts
Control vs data plane
APIs, ledgers, and metadata stay in your services. Bytes and hot reads often should not.
Async by default
Queues and workers keep user requests off vendor I/O, ranking, and fan-out.
Common mistakes
- Adding search, replicas, and a CDN to every diagram.
- Never saying what you would not build.
Interview tips
- Start with QPS, payload size, and consistency needs.
- Name one failure mode and how the design degrades.
Related challenges
Built by Al Beltran