Founded
2017
Starting Price
Free
Category
Developer Tools
Last updated April 26, 2026
About ZenUML
ZenUML is a diagram-as-code tool that lets developers create sequence diagrams, flowcharts, and other UML diagrams using a concise text DSL. Diagrams render in-browser with no server-side processing, and the tool is available as a free web app, Confluence plugin, IDE extension, and desktop app.
Pros & Cons
Pros
- Concise DSL produces diagrams with far less code than Mermaid or PlantUML
- Privacy-first browser rendering keeps diagram data local
- Free web editor is fully featured with no signup
- Excellent Confluence integration consolidates multiple diagram tools
- Interactive code-to-diagram highlighting speeds up reviews
Cons
Key Features
Diagram-as-Code
Write sequence diagrams using a concise text DSL that requires 2-3x fewer lines than competitors.
Real-Time Rendering
Diagrams render instantly in the browser as you type, with no server round-trips.
Interactive Diagrams
Code and rendered diagram stay synchronized with click-to-highlight navigation.
Privacy-First
All processing happens client-side so diagram source never leaves your browser.
UML 2.5.1 Compliant
Follows the OMG UML 2.5.1 standard with practical extensions for modern engineering teams.
Confluence Integration
Native Atlassian Marketplace app for embedding diagrams directly in Confluence pages.
Multi-Platform
Available as a web editor, Confluence app, IDE extension, and desktop application.
Pricing
Web Editor
Free
- Unlimited diagrams in browser
- Sequence diagrams, flowcharts, mindmaps
- Export to PNG/SVG
- No account required
Confluence App
Freemium
Best For
API Sequence Documentation
Document service-to-service API call flows in code reviews and design docs.
Confluence Technical Docs
Embed live, editable sequence diagrams inside engineering Confluence spaces.
System Design Interviews
Quickly sketch and iterate on architecture flows during design discussions.
Onboarding Diagrams
Maintain version-controlled sequence diagrams alongside code for new engineers.
