To configure the backend in the Add-on Configuration tab of CONFLUENCE_BASE_URL/admin/drawioConfig.action, a list of key=value entries can be added. Currently, the following keys are supported:

  • htmlscale: Specifies the scale used for rendering HTML labels on the server-side. This setting is used for creating and exporting images in Safari and IE11 and earlier, if useExternalImageService is not enabled. The default value for this setting is 0.6 (in version 6.5.6) or 0.63 (in later versions) on Linux and 0.75 on all other operating systems. It defines the ratio between px units for rendering HTML and the units used for rendering other graphics elements.
  • externaliconsearch: A flag that controls whether or not to enable the use of external image search service when searching for icons in editor. Default settings enables external icon search. Using externaliconsearch=0 disables it.
  • vsdurl: URL of the .vsd converter
  • customlibs: A switch that toggles the custom libraries feature. Set it to 0 to disable custom libraries, otherwise they are enabled.
  • plantuml: Enables the SVG generation using Plant UML syntax. The PlantUML server is not built into You can either use the service we provide at or host PlantUML server yourself and reference that.
  • viewerurl: HTML exported diagrams require a JavaScript file to display. This is the URL of the viewer JavaScript file which can be hosted within the intranet. If left blank, it defaults to