appwrite/docs/services/functions.md

The Functions service allows you to create custom behaviour that can be triggered by any supported Appwrite system events or by a predefined schedule.

Appwrite Cloud Functions lets you automatically run backend code in response to events triggered by Appwrite or by setting it to be executed in a predefined schedule. Your code is stored in a secure and encrypted way on your Appwrite instance and is executed in an isolated enviornment.