Chatfuel Contacts API
The only documented Chatfuel API operation as of 2026-08-13. POST https://panel.chatfuel.com/api/contacts/{automation_id}/whatsapp/ imports a batch of up to 1,000 WhatsApp phone numbers into an automation and assigns a shared set of contact properties to every number in the batch, so a CRM can sync audiences into Chatfuel and trigger a broadcast off a property change. Authenticated with an account API token from Settings -> API sent as Authorization Bearer; an unauthenticated call returns HTTP 401.