CRAYON-C4 vs draw.io for C4 diagrams

Last updated: 28 September 2026

draw.io (also known as diagrams.net) is a free, general-purpose diagramming tool with a C4 shape library. It is not a C4 modeling tool — there is no underlying model, so the boxes on your Context diagram and the boxes on your Container diagram are separate drawings that happen to look related. CRAYON-C4 is C4-native: you define elements and relationships once, and every diagram (Context, Container, Component, Code, plus behavior and deployment) is a view generated from that one model.

Capability comparison

Capability	CRAYON-C4	draw.io
C4 model support	✓	Partial
Behavioral flows (F4)	✓	—
Generate the model from code	✓	—
No DSL required	✓	✓
Multi-audience views	✓	—
Zero setup (web)	✓	✓
Free solo tier	✓	✓
Team collaboration	✓	—
A real underlying model (not just shapes)	✓	—
Diagrams stay in sync when the model changes	✓	—

When to choose draw.io instead

Choose draw.io if you need a free, general-purpose canvas for diagrams that are not C4 at all — network topology, flowcharts, ER diagrams, org charts — or if your C4 diagrams are genuinely one-off illustrations that will never need to stay consistent with each other as the system changes. It has no seat limits, no account required, and a huge shape library beyond C4.

When to choose CRAYON-C4

Choose CRAYON-C4 the moment you have more than one C4 diagram of the same system and need them to agree with each other. Rename an element once and every diagram it appears on updates — there is no "also fix the Container diagram" step to remember. CRAYON also adds behavioral flows and deployment views on the same model, and can generate a first draft from a real codebase, none of which a blank canvas can do for you.

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