Compare software

Mermaid vs D2: catalog facts
Mermaid	D2
Free Free and open source under the MIT licence.	Free Free and open source under the Mozilla Public License 2.0.
Web, Command line	Windows, Command line
Diagrams are plain text, so they diff and review like code Rendered natively by GitHub, GitLab and most documentation generators	Diagrams as text that fit into version control Simple syntax with automatic layout
Layout is automatic, so fine control over positioning is limited Complex diagrams become hard to read in source form	Requires learning the D2 syntax Less fine control than drawing by hand
Web application, Downloadable app	Downloadable app
Open source	Open source
License: MIT	License: MPL-2.0
Not stated if an account is needed	No account needed
Not stated if it works offline	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.