With the diagrams.net configuration app you can edit your custom configuration for diagrams.net. This app will generate a custom configuration based on the information from the diagrams.net helpdesk (see here). You are able to add custom colors, presets and fonts to diagrams.net.
You can open the configurator on drawio-config.herokuapp.com
If you open diagrams.net (either on diagrams.net or as desktop app) you need to open the diagrams.net Configuration … from the Extras menu. Paste the json string that you copied from this app into the input field and press the apply button. You need to restart diagrams.net to apply the configuration.
This app is build with create-react-app and can also run on your local mashine (node/npm needs to be installed):
#-- using yarn: --
yarn
yarn start
# -- using npm: --
npm install
npm run start