Compare software

Mermaid vs SequenceDiagram.org: catalog facts
Mermaid	SequenceDiagram.org
Free Free and open source under the MIT licence.	Free Free to use, supported by optional Patreon donations.
Web, Command line	Web
Diagrams are plain text, so they diff and review like code Rendered natively by GitHub, GitLab and most documentation generators	Text notation and drag and drop editing in one tool Saves to local files, Google Drive, OneDrive or browser storage
Layout is automatic, so fine control over positioning is limited Complex diagrams become hard to read in source form	Only draws sequence diagrams No built-in real-time collaboration mentioned
Web application, Downloadable app	Web application
Open source	Closed source
License: MIT	License not stated
Not stated if an account is needed	No account needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 22, 2026	Official website Full listing and sources Checked October 2, 2026

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