Free editor / free UML editor
free UML editor

Free UML editor for software diagrams online

Use diagram.now when a software design needs a diagram before it needs a formal tooling decision. Draft UML class diagrams, sequence diagrams, component diagrams, deployment diagrams, and architecture sketches in the browser.

Start a free UML diagram Use in Confluence

Best first template

UML sequence diagram for login, token refresh, and service authorization.

Start in your browser

Draw, export or share the diagram first. Install the Confluence app only if it belongs in your team's docs.

Confluence upgrade

When the diagram belongs in a spec, runbook, ADR, or process page, install diagram.now so it stays editable beside the docs.

Make design reviews easier to scan

A UML diagram helps reviewers understand structure and flow before they debate implementation details. Keep the first version simple: the classes, services, dependencies, or sequence that matter for the decision.

UML diagrams that belong in docs

Use UML for API auth flows, service boundaries, deployment topology, domain models, major classes, state transitions, and integration contracts.

Move long-lived UML into Confluence

If the diagram becomes part of an ADR, RFC, implementation plan, or onboarding page, use the Confluence app so teammates can update the visual where the discussion already happens.

Start free, then bring it into Confluence

Use the browser editor for the first draft. If the diagram becomes team documentation, install diagram.now from Atlassian Marketplace and keep it editable inside Confluence.

Currently $0 for Confluence sites with up to 10 users. Bring one real diagram — Visio (.vsdx), Lucidchart, Mermaid or SQL — and we'll help you import it into Confluence in a free one-file migration session. Request migration help.

Start drawing free Install from Atlassian Marketplace

FAQ

What UML diagrams can I create?

Use diagram.now for common UML-style diagrams including class, sequence, component, deployment, package, activity, and state-oriented visuals.

Is the UML editor free?

Yes. The browser editor is free to use. If your team wants to edit diagrams inside Confluence pages, install the diagram.now app from the Atlassian Marketplace.

What is the fastest UML diagram to start with?

Start with a sequence diagram for one user action or a class/domain model for one bounded part of the system.

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