Feature announcement: now do way more with webhooks
One of our most popular features in Postmark is webhooks, which give you the ability to receive real-time notifications for events like bounces, opens, and clicks in the form of HTTP POSTs to a URL you specify. This allows you to take action on various email events without having to make any calls to our API. For example, you can use bounce webhooks to mark an email address in your application as inactive, and provide your users with a way to correct their email address if they entered it incorrectly in your application.
Up to now these webhooks have been limited. You were only able to add a single URL for an event, and you were only able to get notifications for one event at a time. Itâs still a useful feature, but this 1:1 relationship between URL and event was holding back some of the more powerful things you can do with webhooks.
Well, weâre happy to say that with the introduction of fully modular webhooks, all of that is changing today. Iâll first list out all the new functionality we released today, and then go into more detail on the UI changes. Hereâs whatâs new:
- With modular webhooks you can now choose which events youâd like to send to each specified URL. Want to send Open and Click events to the same URL? You got it. Want to drink from the firehose and send all events to a single URL? Have at it!
- With this change, youâre also now able to add up to 10 URLs for us to POST to. Letâs say, for example, you want to get Bounce events to your internal system, but you also want to use our nifty Slack App to send Bounce notifications to a channel of your choice. You can now do that!
- In the past, the Spam Complaint event was part of the Bounce event. This created a bunch of confusion and frustration, since spam complaints generally require different actions than, say, a hard bounce. With this release Spam Complaints have been moved out into a separate event, so that problem is also a thing of the past.
- Youâve always been able to add basic HTTP auth via the webhook URL, but weâve now added HTTP auth fields in the UI as well.
- We added an option to include up to ten custom HTTP headers with every webhook.
- Webhooks now live in their own tab on the Settings page, instead of being buried in the âOutboundâ tab like it used to be. Note that the Inbound webhook remains in the âInboundâ tab for now.
Adding and managing modular webhooks #
The main webhooks page now looks like this, and will list out all the webhooks youâve set up:

To add a new webhook, click the âAdd webhookâ button, which takes you to a basic two-step process:
- Enter the URL where youâd like to receive HTTP POST requests.
- Select which events youâd like to get notifications for. Choose from Delivery, Bounces, Spam complaints, Open, and Link clicks.

You can then test your webhook by sending some sample JSON to the URL before you save it. If youâd like to add custom headers and basic HTTP auth, you can do so by expanding that section, but this is optional:

Youâll notice that we added a RecordType
field to the JSON payload to identify the different events youâll receive in each webhook. Have a look at the developer docs
One important note: we did not update the Servers API with this release. This wonât affect many of you, since that API is only used to set up or edit new webhooks â most customers do this via the UI. But for those of you who use the API to manage webhooks, the existing API endpoint will continue functioning as it does currently. Youâll be able to set one webhook URL per event, and change that URL. But you wonât be able to set up modular webhooks with the public API yet â youâll have to use the UI for that. Weâll release a future update to bring this functionality to the Servers API as well.
What about the âoldâ webhooks? #
We havenât changed the payload format for existing webhooks, so everything youâve set up will continue working as before. For example, if you have currently have a bounce webhook defined, it will still post both bounces and spam complaints to it as it did before. If youâd like to split out spam complaints, youâd have to change your existing webhooks to be modular.
And thatâs it! Weâre excited to see how you use this new webhook functionality. So, in addition to our usual request to let us know what you think and how we can improve, weâd love it if you could tell us how youâll be using this feature. Drop us a line at support@postmarkapp.com.