Three things to know: the protocol, the credential, and what the alert payload looks like. The setup is the same on free and Pro.
The grid below describes what the channel itself supports once wired up. All channels are available on the free plan unless the badge says otherwise.
You self-host Matrix or use an EU-hosted one for privacy reasons. End-to-end encrypted rooms are supported as long as the bot account is in the room.
Free plan. No card. Cancel any time.