Free editable template · .excalidraw

A system design interview board you can adapt

Keep requirements, APIs, data flow, storage and trade-offs visible while you reason through a design. This board is a starting structure, not a memorised answer.

How to use the board

Begin by clarifying the users and the operation you are designing. Add scale and latency assumptions, name a small API surface, then trace one request from client to storage. Add a queue or cache only when a requirement justifies it.

Adapt it to your system

1. Replace the example names with responsibilities your audience recognises.
2. Label arrows with what crosses the boundary: requests, events or stored records.
3. Mark trust boundaries and note which components own important data.
4. Record a failure case and a trade-off beside the design, then simplify anything unnecessary.

Assumptions and limits

The worked example is deliberately small. It does not establish capacity, prove a consistency model or choose the right database for every workload. Explain your assumptions and revisit the design when they change.

Source and reuse

Original template by Blankpaper, released under Creative Commons Attribution 4.0. You may adapt and share it with credit. No interview outcome is promised.

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