The Only 5 Diagramming Tools You Need for System Design
The tools I actually use (and recommend to my mentees)
When you’re preparing for system design interviews or documenting architecture at work, having the right diagramming tool makes a difference.
Here are my top picks for creating clear, professional system design diagrams.
1. Excalidraw
This is my go-to tool for system design work, and it’s what I recommend to everyone I coach.
Excalidraw gives you a hand-drawn aesthetic that feels approachable. It’s free, runs in your browser, and has virtually no learning curve. You can start sketching architecture in seconds.
What makes it perfect for system design practice is the flexibility. You’re not locked into rigid shapes or connectors. You can quickly iterate on designs, which is exactly what you need when you’re working through a problem in an interview setting.
For paid subscribers: I’ve created two resources to accelerate your practice:
My Excalidraw System Design Template – copy it and adjust when you practice, so you’re not starting from scratch every time
My System Design Component Library – essential Excalidraw components for databases, load balancers, caches, queues, and more
2. Draw.io
The Swiss Army knife of diagramming tools. It’s free, feature-rich, and integrates with Google Drive, Dropbox, GitHub, and Confluence.
The template library is massive, covering flowcharts, network diagrams, process maps, and more. Best for polished, professional diagrams you need to share with stakeholders or embed in documentation.
3. Lucidchart
The enterprise standard. If your company already uses it, lean into the template library and real-time collaboration features.
Works well for team environments where multiple people need to contribute simultaneously, with live updates and commenting built in.
4. DiagramGPT
Describe what you want in plain text, and it generates the diagram. Useful for quick iterations or when you’re exploring ideas and don’t want to manually place boxes yet.
You can tweak the output afterward, adjusting layout and colors to fit your needs.
5. Diagramming AI
Smart generation from simple descriptions and an interactive chat interface. You can make modifications using natural language commands and get suggestions as you build.
Integrates with other tools to streamline your workflow.
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🎁 The System Design Interview Preparation Cheat Sheet
If you’re into visuals, paid subscribers unlock:
→ System Design Walkthroughs of Popular Interview Questions
→ My Excalidraw system design template – so you have somewhere to start
→ My Excalidraw component library – used in the diagram of this issue
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All good choices. But no Mermaid option?
I’d add that the real value is choosing the tool that matches the phase of thinking.