Grafana OnCall has expanded its webhook support to allow integration with messaging services like Mattermost and Discord, enabling users to receive alert notifications and updates in these platforms. The integration involves creating bots that post details of alert groups to designated channels, keeping the status and information up to date through Grafana OnCall webhooks. For Mattermost, users must create a bot account to access the API and configure webhooks to post and update messages based on alert group activity, while for Discord, users can set up webhooks to create and edit messages using a similar process. The guide also mentions the potential for extending this approach to other services like Microsoft Teams and Google Chat, and offers script resources for programmatically setting up webhooks with the Grafana OnCall API. The text concludes by promoting Grafana Cloud, highlighting its ease of use and free tier offerings.