Compare software

nomnoml vs Mermaid: catalog facts
nomnoml	Mermaid
Free Free and open source under the MIT licence.	Free Free and open source under the MIT licence.
Web, Command line	Web, Command line
Readable syntax that resembles the drawn diagram Instant live preview in the browser	Diagrams are plain text, so they diff and review like code Rendered natively by GitHub, GitLab and most documentation generators
Web editor stores diagrams only in browser local storage Smaller range of diagram types than PlantUML	Layout is automatic, so fine control over positioning is limited Complex diagrams become hard to read in source form
Downloadable app, Web application	Web application, Downloadable app
Open source	Open source
License: MIT	License: MIT
No account needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked September 22, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.