Prepare the whiteboard

Choose your diagramming tool before the interview — not during it. 90% of the time the interviewer will ask you to share your screen and hand you nothing.

If you prefer visual tools, have a template ready in Figma, Miro, or even Excalidraw with pre-made components: server, database, cache, CDN, load balancer. Copy-paste these in the interview, don't draw from scratch, it will save a lot of time.

If you think in UML, make sure your tool actually renders it live. No one wants to stare at raw PlantUML text.

This sounds obvious, but it matters:

• A clean diagram looks more professional than boxes drawn with a trackpad.
• A familiar tool means you're thinking about the architecture, not fighting the interface.
• You'll finish faster and have more time to defend your decisions.