Webhook
An HTTP callback that sends real-time data between systems when an event occurs (e.g. new lead, payment received, ticket created). AI agents and no-code tools use webhooks to trigger workflows automatically—connecting CRMs, help desks, calendars, and custom apps without polling on a schedule. For Headless Agent deployments, webhooks are the dominant trigger pattern.
Written by Max Zeshut
Founder at Agentmelt · Last updated Sep 9, 2026
Example
A new ticket in Zendesk fires a webhook to an AI support agent's endpoint with the ticket payload. The agent reads it, drafts a reply, and either sends or escalates within 4 seconds—no polling, no batch delay. The same agent stays idle (and costs nothing) until the next webhook arrives.
Frequently asked questions
- How do you secure agent webhook endpoints?
- Three controls every production setup needs: (1) verify the webhook signature on every request (HMAC with a shared secret), (2) allowlist source IPs where the sending service publishes them, and (3) treat the payload as untrusted input regardless—the same scrutiny you give user messages applies to webhook content. Unsigned webhooks are a common path for attackers to inject malicious data into the agent's context.