Webhook Format
Selu does not have a standalone webhook system. Webhook-based messaging is handled through Pipes.
Certain pipe types (for example, the Telegram pipe) receive inbound messages via token-based webhook endpoints specific to that pipe. The webhook URL and authentication are configured as part of the pipe setup, not through a separate webhook subsystem.
There are no outbound webhooks, no HMAC signature verification headers, and no subscribable event system.