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PlantUML vs Mermaid: catalog facts
PlantUML	Mermaid
Free Free and open source under the GPL.	Free Free and open source under the MIT licence.
Windows, macOS, Linux, Web, Command line	Web, Command line
Covers far more diagram types than most text-based tools Integrations for nearly every editor, wiki and documentation system	Diagrams are plain text, so they diff and review like code Rendered natively by GitHub, GitLab and most documentation generators
Requires Java and, for some diagram types, Graphviz The syntax is inconsistent between diagram types	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: GPL-3.0	License: MIT
Not stated if an account is 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 September 22, 2026	Official website Full listing and sources Checked September 22, 2026

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