Do I need an account to use UMLet Collab?

No. Create a project and send its link. Anyone with the link can open and edit it.

Can several people edit a UML diagram at the same time?

Yes. Everyone sees each other's cursors and selections, and changes appear as they happen.

Can I import and export UMLet diagrams?

Yes. Diagrams are standard UMLet .uxf files. You can import them and export .uxf, PNG, SVG or PDF.

Draw UML diagrams together, live

Q: Is it free?

Yes. It is free to use and open source.

No sign-up. Everyone with your project’s link edits the same diagrams at the same time.

Create a projectIt holds up to 40 diagrams, each in its own tab. Everything saves automatically.
Share the linkSend it to your team. Whoever has it can edit with you, live.
Private by defaultProjects aren’t listed anywhere. Only people you send the link to can find yours. Projects nobody opens for 2 months are deleted.

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About UMLet Collab: what it is, what it can do, FAQ

A real-time collaborative UML editor in your browser

UMLet Collab is a free online UML diagram tool for teams, students and anyone who draws diagrams with other people. It is built on UMLet, the popular open-source UML editor, and its web version UMLetino, and adds live collaboration: several people edit the same diagram at the same moment and see each other’s cursors, selections and changes as they happen. There is nothing to install and no account to create.

What you can draw

It keeps UMLet’s fast, text-driven way of drawing and its palettes for the standard UML diagram types:

class diagrams and object diagrams
sequence diagrams
use case diagrams
activity diagrams and state machine diagrams
package, component and deployment diagrams
plus free-form boxes, notes and your own custom elements

How collaboration works

Create a project and copy its link with the Share button. Anyone who opens the link joins the project: they see the same diagrams, with a coloured cursor and name for every person, and edits sync instantly. When two people type in the same element, their text is merged rather than overwritten. Everything is saved automatically on the server, so you can close the tab and come back to your diagrams later, and each diagram keeps a version history you can restore from.

Projects with many diagrams

A project holds up to 40 diagrams, shown as tabs. You can add, rename, reorder and delete diagrams, and bring deleted ones back. Your own UMLet files work too: import a .uxf file, or export a diagram as .uxf, PNG, SVG or PDF.

Privacy, limits and housekeeping

Projects are private by default. They are not listed or searchable anywhere, and only people who have the link can open them, so share the link only with people you want to edit with.
Anyone with a project’s link can edit and delete it.
Projects nobody opens for 2 months are deleted, and deleted projects are erased for good after 30 days. Until then they can be restored from their link.
To keep it free for everyone, a network can create up to 5 new projects a month.

Frequently asked questions

Do I need an account?

No. Create a project and send the link.

Is UMLet Collab free?

Yes, it is free to use and open source.

Is it the same as UMLet?

It is a fork of UMLet’s web editor with real-time collaboration added. Diagrams use the same .uxf format, so files move between UMLet, UMLetino and UMLet Collab.

Can I host it myself?

Yes. The code is on GitHub and runs on Cloudflare Workers’ free plan, or locally with Node.