Free Sequence Diagram Generator
Create UML sequence diagrams with our free tool. Document interactions between system components.
- Participant and lifeline creation
- Synchronous and async messages
- Return messages and self-calls
- Activation bars
- Alternative and loop fragments
- Export as PNG, SVG, or Mermaid
Frequently Asked Questions
What's the difference between sync and async messages?
Synchronous messages (solid arrow) wait for response before continuing. Asynchronous messages (open arrow) continue without waiting. Use async for non-blocking operations.
What are combined fragments?
Fragments like 'alt' (if/else), 'opt' (optional), and 'loop' show conditional or repeated behavior. They group messages with conditions or iteration.
Should I show return messages?
Show returns when the response carries meaningful data. Omit for simple acknowledgments to reduce diagram clutter. Be consistent within your diagram.
Is the sequence diagram generator free to use?
Yes, this tool is completely free with no hidden fees or premium features. Create unlimited items and download all generated code without any restrictions.
Do I need to sign up to use this tool?
No signup or account is required. Simply visit the page, configure your settings, and export the code immediately.
Can I use the generated code in commercial projects?
Absolutely! All generated code is free to use in both personal and commercial projects without attribution or licensing restrictions.