What are email webhooks?
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Most ESPs show you email metrics in a dashboard. That's fine for checking in, but it's not great if you need the data somewhere else: your CRM, your database, a custom analytics tool, or a workflow that fires when someone bounces. Webhooks solve that problem.
A webhook is a way for your ESP to push event data to your server in real time. Instead of you going to pull the data (polling an API), the ESP sends it to you the moment something happens. Someone opens your email, someone clicks a link, someone marks it as spam: your ESP fires an HTTP POST request to a URL you've specified, containing the event data. Your server receives it and does whatever you've set it up to do.
What events can trigger webhooks?
The specific events depend on your ESP, but most support: delivery (accepted by the recipient's server), open, click, bounce (soft and hard), unsubscribe, spam complaint, and sometimes conversion events if you have tracking set up.
Each event payload typically includes the recipient's email address, the message ID, the timestamp, and event-specific data (for clicks, the URL they clicked, for bounces the error code and reason).
Why use webhooks instead of the ESP dashboard?
Because the dashboard is a window. Webhooks are a data pipe. With webhooks, you can: immediately suppress bounced addresses in your own database, trigger a CRM update when a sales prospect clicks a link, feed deliverability data into a monitoring tool, or run custom analytics that your ESP doesn't offer natively.
But if you're processing webhook data for reporting, you'll need somewhere to receive and store the events. Most developers set up a simple endpoint that logs events to a database, then query from there.
Do all ESPs support webhooks?
Most do, though the naming varies. Mailchimp calls them "webhooks." Postmark and SendGrid call them "event webhooks" or "inbound webhooks." Check your ESP's developer documentation under "webhooks," "callbacks," or "event notifications."
If you're trying to use bounce webhook data to keep your list clean in real time, that data can also feed into validation workflows. If you want help wiring that up, our SOS hotline can point you in the right direction.
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