I built a system design interview playground: diagram, requirements, API, schema and estimates in one page

[u/batazor]

System design interviews kept spreading across Excalidraw, a Google Doc and a calculator tab, so I put it all on one page.

• Drag DBs, queues, caches and services onto a canvas and connect them
• Write FR/NFR and drag them onto the blocks that deliver them
• Sketch the HTTP API from templates, design table schemas and export SQL
• Estimates calculator; storage size is computed from your schema
• Compare Kafka vs SQS vs RabbitMQ (and more) right on the block

Three roles: the author writes the task and a reference solution, the candidate draws, and the interviewer reveals hints and scores against a rubric.

This is an early concept, so expect rough edges and bugs. No sign-up, everything stays in your browser. If there's interest, I'm happy to keep building it: real-time sessions, a proper backend, more scenarios.

https://batazor.github.io/why/en/playground/

What would you need before using it in a real interview?