When an HTTP request is received built-in connector
The When an HTTP request is received connector can use incoming API calls as triggers and actions.
When used as a trigger, the When an HTTP request is received connector automatically generates the URL, which can be used as a POST method.
After it's saved, the URL is generated.
The http trigger also can determine who can trigger the flow. There are three options:
Any user in my tenant
Specific users in my tenant
Anyone
Templates are also available in Power Automate that use the When an HTTP request is received and Response connectors. Search for http in the templates section of Power Automate.
