Open source gems
Mermaid
A text-based diagramming library for flowcharts, sequence diagrams, state diagrams, and documentation-friendly charts.
- Pricing
- Free
- Login required
- No
- API available
- No
- License
- MIT-style open source library; verify the current repository license before redistribution.
- Last checked
- 2026-07-09
What it is
Mermaid is a good reminder that diagrams do not have to begin as images. A small block of text can describe a flow, sequence, or state machine, then render into a diagram that reviewers can edit in plain text.
It works best for living documentation: architecture notes, onboarding pages, release flows, and bug triage diagrams. If the diagram needs pixel-perfect illustration, use a canvas tool. If it needs to stay close to code and change often, start with Mermaid.
Why worth a look
A text-based diagramming library for flowcharts, sequence diagrams, state diagrams, and documentation-friendly charts.
Good for
- Turning architecture or process notes into diagrams that can live beside code.
- Teaching systems, workflows, and sequences without opening a heavyweight design tool.
How to start
- Open the live editor and paste a small flowchart.
- Move the diagram text into a README, issue, or docs page after it communicates the idea.
Best first click
Open the Mermaid Live Editor and modify one example diagram before reading the full syntax guide.
Trust facts
- Pricing
- Free
- Login required
- No
- Open source
- Yes
- API available
- No
- License
- MIT-style open source library; verify the current repository license before redistribution.
- Risk
- Complex diagrams can become hard to maintain if the source text is not kept close to the documentation.