Desktop App Custom Dictionaries

Mattermost Desktop App users running Windows or Linux can download dictionary definitions from a custom URL. If custom dictionaries aren’t specified, default dictionary definitions are obtained automatically from Chromium’s CDNs.

This feature is available in the Mattermost Desktop App from v4.7.1 on Windows and Linux. Custom dictionaries are not supported in the Mattermost Desktop App on macOS.

Setting up the dictionaries

The Mattermost Desktop App uses Hunspell Dictionary definitions for Windows and Linux. For macOS, dictionary definitions are provided by Apple within the operating system itself. A quick way to access default dictionary definitions is to obtain a copy of from the latest electron release.

Once downloaded, the dictionary definitions need to be extracted and converted to lowercase because chromium expects en-us rather than en-US…. These defitions are ready to use and would match the usage of using Chromium’s CDN ones without accesing it, but they could also be modified to fit specific needs.

Serve the files from a web server, and write down the URL to the root folder of the dictionaries for using it in the Desktop App.

Configuring the Desktop App

Open the Mattermost Desktop App, go to … > File > Settings. Under App Options, ensure that the Check Spelling option is enabled. Below this setting there is a link named Use an alternative dictionary URL. Use this option to specify the URL to the root folder of the dictionaries, then select Save.

Removing customized dictionaries

To stop using the specified dictionary definitions, select the Revert to default preference option under the input box in the App Options to use Chromium’s CDNs instead.