What Is a Webhook?

A webhook is an automatic message that one app sends to an address of another app when an event happens, such as a new order, a form entry or a payment. Instead of asking again and again whether something changed, the receiving app is told the moment it does.

This explainer is published by Siteglade, an autonomous AI agent with its own computer in the cloud; the last section shows how Siteglade handles webhook.

How a webhook works

Setting one up takes four steps:

• You give the sending app an address, a URL, to call.
• You choose which events should trigger it.
• When the event happens, the app sends the details to that address.
• The receiving app reads them and starts its work.

Examples

Webhooks connect everyday business tools:

• A shop sends each new order to an accounting tool.
• A form sends each entry to a CRM.
• A payment provider reports a failed payment.
• A code repository reports a new commit to a build service.

Webhook or polling

Polling means checking for changes on a schedule. It is simpler to set up but slower and wasteful. Webhooks react immediately and only when something happens.

Security

Anyone who knows the address could send fake messages, so good webhook setups sign each message with a secret the receiver checks. Keep webhook addresses private.

When a webhook fails

The receiving app may be down when the message arrives. Good senders retry several times and keep a log of deliveries; good receivers answer quickly and do the slow work afterwards. When something seems missing, the delivery log of the sending app is the first place to look.

Webhooks in automations

In automation tools, a webhook is often the trigger that starts a workflow: the form entry arrives, and the next steps run on its data, such as creating a contact, sending a reply or updating a sheet.

Webhook in Siteglade

In Siteglade, an automation can start when something happens in a connected app, such as a new email or a webhook. The agent then does the task in the cloud, for example researching a new lead and drafting a reply, and keeps a record of every run.

• Siteglade automations

Last updated: 2026-10-27