PlantUML vs SequenceDiagram.org (2026): which should you pick?

Pick PlantUML if

• Fits if you want diagrams stored as text next to your code
• Works for teams documenting systems in wikis or Markdown

Look elsewhere if

• Skip it if you want to drag shapes around a canvas
• Not for you if you sketch freehand, because it has no whiteboard
• Watch out: layout is decided by the engine, so fine control over placement is limited
• Watch out: only the GPL build has every feature, and other license builds lack some such as ditaa

Pick SequenceDiagram.org if

• Fits if you draw sequence diagrams and want them stored in your own Drive
• Works for people who want diagrams processed in the browser, not on a server

Look elsewhere if

• Skip it if you want a freeform whiteboard: sequence and architecture diagrams only
• Not for you if you need live co-editing, because sharing is by link or saved file
• Watch out: the code is not open source, and the paid on-prem Docker version has no published price
• Too light for team spaces: there are no accounts or shared workspaces listed

PlantUML

• Layout is controlled by the engine; the FAQ says it gives less control over placement than drag-and-drop tools.
• Diagrams are written in code, so there is no visual canvas for freehand sketching.
• Builds under licenses other than GPL lack some features, such as the ditaa integration.

SequenceDiagram.org

• It covers sequence and architecture diagrams only, not freeform whiteboarding.
• The code is not available under an open-source license.
• There is no real-time multi-user editing; sharing is by link or saved file.
• The on-prem Docker version is a paid perpetual license, but its price is not published.

PlantUML

Text-to-diagram language

Diagrams are written as short text and drawn from it, so changing the text updates the picture.

UML and non-UML diagrams

Supports sequence, use case, class, object, activity, component, deployment, state and timing diagrams, plus Gantt, MindMap, WBS, wireframe and others.

In-browser editor

The home page has an editor that runs in the browser with a JavaScript rendering engine and redraws as the code changes.

Many integrations

The Running page lists connections to wikis and forums, editors and IDEs, including Confluence, MediaWiki, IntelliJ IDEA and Eclipse.

Several license options

The download page offers jars under GPL, LGPL, Apache, BSD, EPL and MIT; the GPL build is the one with every feature, such as ditaa.

SequenceDiagram.org

Text and drag-and-drop together

A diagram is described in a text script and can also be edited by clicking and dragging on the drawing.

Client-side processing

All parsing, processing and drawing happens in the browser, which the site says means diagram data is not transferred over the internet.

Saving and sharing

Diagrams save to a file, Google Drive, OneDrive or browser storage, and a share link can be generated.

Export

Export as SVG with the source text embedded, or as PNG; PDF is produced by printing from the browser.

Architecture diagrams

Besides sequence diagrams the editor can create architecture diagrams, which need a recent Chrome, Edge, Firefox or Safari.

Plugins and on-prem

Plugins exist for Confluence Cloud and IntelliJ IDEA, and a Docker image is offered for internal company use.

PlantUML

• Open source$0

  Free jar and source code under your choice of license; you run it yourself or use the online editor.

SequenceDiagram.org

• Web app$0

  The browser editor is free to use; the site invites voluntary Patreon support from $1 a month.