Viewer

PlantUML viewer that stays on your device

Most online PlantUML tools send your text to a server to draw it. This one draws it inside your browser. Open a .puml file or type, and export when you are done.

Open the PlantUML viewer Free. No sign-up. Nothing is uploaded.

What you get

Live previewThe diagram redraws as you type. Errors are shown in the status line.
FilesOpen .puml, .plantuml and .pu files, and save your source back.
ExportSVG, PNG, standalone HTML and PDF.
TemplatesReady-made starting points for common diagram types.
ConvertOne click to Mermaid or draw.io when you need another format.

How it stays private

Rendering and converting both run inside your browser. The page is not allowed to open connections to other servers, so your diagram text is not uploaded. Your work is kept in your browser's local storage only. Details are in the privacy policy.

The PlantUML renderer is bundled with the page, so there is no server that could receive your text.

Questions

Does it work offline?

After the page has loaded, rendering does not need the internet. Open each format once before going offline so its renderer is loaded.

Is every PlantUML feature supported?

The bundled renderer is a build of PlantUML itself, so the common diagram types work. Features that need outside resources, such as including files from a URL, do not work, because the page is not allowed to make connections.

Is it free?

Yes. There is no account and no paywall.