A major mode for editing PlantUML sources in Emacs
Emacs Lisp
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LICENSE.txt Initial import Jun 11, 2012
README.md #20 Added usage documentation May 7, 2016
banner.png Added banner Sep 21, 2015
puml-mode.el Bumped version number Jul 19, 2016



PlantUML mode for Emacs

puml-mode in action

“Pummel me all you want," I say. "Pummel me to death, in fact. My answers will not change." The Invierno step back, frowning. "You must love her very much," he says, not unkindly.”

from The Bitter Kingdom - Fire and Thorns #3

A PlantUML major mode for Emacs.


Make sure you have MELPA enabled in your emacs.d. Then, you can just

M-x package-install<RET>

Also, to enable preview you need to tell puml-mode where to locate the PlantUML JAR file. By default it will look for it in ~/plantuml.jar, but you can specify any location with:

M-x customize-variable<RET>


  • Syntax highlight
  • Autocompletion
  • Preview

Enable the major mode

You can automatically enable puml-mode for files with extension .puml or plantuml by adding the following to your .emacsrc:

;; Enable puml-mode for PlantUML files
(add-to-list 'auto-mode-alist '("\\.puml\\'" . puml-mode))
(add-to-list 'auto-mode-alist '("\\.plantuml\\'" . puml-mode))

Of course, you can always enable manually the major mode by typing M-x puml-mode once in the desired PlantUML file buffer.


You can either tell puml-mode to autocomplete the word before the cursor by typing M-x puml-complete-symbol. This will open a popup with all the available completions as found in the list of keywords given by running PlantUML with the -language flag.

To render the PlantUML diagram within Emacs, you can also hit M-x puml-preview. This will run PlantUML and display the result in the *PUML-Preview* buffer. The format used to render the diagram is automagically chosen from what's supported by your Emacs. It will be one of the following, in order of preference:

  • SVG
  • PNG
  • Unicode ASCII art

Default key bindings

The following shortcuts are enabled by default:

C-c C-c  puml-preview: renders a PlantUML diagram from the current buffer in the best supported format

C-u C-c C-c  puml-preview in other window

C-u C-u C-c C-c puml-preview in other frame

Integration with org-mode

You can use puml-mode to edit PlantUML source snippets within an org-mode document. To do so, you need to first register it with the plantuml language:

  'org-src-lang-modes '("plantuml" . puml))

Then you can edit a plantuml code block with puml-mode by hitting C-' while inside of the code block itself:

#+BEGIN_SRC plantuml
  <hit C-' here to open a puml-mode buffer>

When in the puml-mode buffer you can then hit again C-' to return to the original org-mode document.


As of v0.6.2 the following commands have been added to help resolving problems:


With debug enabled, the actual command used to invoke PlantUML is printed into a buffer called *PUML Messages*. You can inspect that buffer to make sure that PlantUML is properly set up, or use it to supply extra information when opening issues.


This project stemmed from the great work of Zhang Weize, and the current code still borrows a lot from it.

Thanks to Pavel G. Koukoushkin for implementing the preview functionality.


Released under the terms of GPLv2. See LICENSE.txt.