Diagrams as code

Diagrams are written as plain text instructions and drawn automatically, so they can be edited, versioned and reviewed like any other text file.
On this pageWhat it is

What it is

Diagrams as code means you describe a flowchart, sequence or other diagram in a short text syntax, and the tool draws it for you. Instead of dragging boxes and arrows around, you write something like "Customer sends order, then Warehouse ships it", and the picture appears. Mermaid is a widely used example.

Why it matters

Hand-drawn diagrams go out of date because editing them is tedious and the source file is often lost. A text diagram can sit next to the documentation, be changed in seconds, and show exactly what changed from one version to the next. Anyone who can edit the text can fix the diagram.

It is most useful for process maps, system overviews and technical documentation that change regularly. For polished visual layouts, such as a marketing graphic, a drawing tool still gives more control.

What to check

  • Which diagram types are supported, such as flowcharts, sequence diagrams, timelines or entity diagrams?
  • Is there a live editor that shows the picture while you type?
  • Can you export to image or vector formats for slides and documents?
  • Can the people who need to read the diagram see it without learning the syntax?

Tools with Diagrams as code

  • Mermaid logo
    Tool
    Mermaid
    Write flowcharts, sequence diagrams and twenty other diagram types as text, then render them instantly.

    Tech stack

    From $10/mo yearlyFree plan
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In Tech stack ranking order; the number is each tool's place. Some of this is collected from public sources and not yet checked by us.