What is a webhook?

Webhook

A webhook is an automated message sent from one application to another when a specific event occurs. Think of it as a notification system between apps: when something happens in one system, it instantly tells another system about it by sending data to a designated URL.

Instead of constantly checking for updates, your applications simply wait to be notified. A customer makes a purchase, and your inventory system knows immediately. A form gets submitted, and your CRM adds the contact without anyone lifting a finger.

How webhooks work

The process starts when you give one application a URL from another application. This URL acts like a delivery address for data.

When the triggering event happens, the source application packages up the relevant information and sends it as an HTTP request to that URL. The receiving application processes the data and takes whatever action you've configured, whether that's creating a record, sending a notification, or kicking off an automation sequence.

Here's a practical example: You connect your ecommerce platform to ActiveCampaign using a webhook. When a customer completes a purchase, your store sends the order details to ActiveCampaign's webhook URL. ActiveCampaign receives that data and automatically adds the customer to a post-purchase email sequence. The whole exchange takes seconds.

Webhooks vs. APIs

Both webhooks and APIs let applications share data, but they work in opposite directions.

An API waits for requests. Your application asks for specific information, and the API responds. Need to check if a contact exists? You send a request. Want to update a record? You send another request. The conversation always starts on your end.

A webhook pushes data automatically. The source application initiates the conversation whenever something noteworthy happens, with no asking required.

APIs give you on-demand access to data and let you create, update, and delete records. Webhooks deliver real-time notifications about events you care about. Most robust integrations use both: webhooks to stay informed about changes, APIs to take action on that information.

Common webhook use cases

Payment notifications. When a customer pays an invoice, your payment processor sends the details to your accounting software and CRM simultaneously. No manual data entry, no delays.

Form submissions. Someone fills out a contact form on your website. A webhook instantly creates a new contact in your email marketing platform and triggers a welcome sequence.

Inventory updates. A product sells out on one channel. Webhooks notify your other sales channels to update availability before you oversell.

Support ticket routing. A high-priority ticket comes in. A webhook alerts your team in Slack and creates a task in your project management tool.

Marketing automation triggers. A lead reaches a certain score in your CRM. A webhook tells your automation platform to move them into a sales-ready sequence.

Setting up webhooks in ActiveCampaign

ActiveCampaign supports webhooks in two ways: receiving data from external sources and sending data when events occur in your account.

To receive webhook data, you'll create a webhook URL in ActiveCampaign that external applications can send information to. This lets you add contacts, update fields, or trigger automations based on events happening elsewhere in your tech stack.

To send webhook data, you'll add a webhook action to your automations. When a contact reaches that step, ActiveCampaign sends their information to whatever URL you specify. Your other applications can then process that data however you need.

The ActiveCampaign app marketplace includes many pre-built integrations that handle webhook configuration automatically. For custom setups, the platform gives you full control over what data gets sent and when.

Webhook best practices

Respond quickly. Webhook requests typically time out after a few seconds. Accept the data immediately and process it asynchronously if the work takes longer.

Handle duplicates gracefully. Network issues can cause the same webhook to fire multiple times. Design your receiving system to recognize and ignore duplicate deliveries.

Verify the source. Webhook URLs are technically public endpoints. Use signature verification or shared secrets to confirm incoming data actually comes from the expected sender.

Log everything. When something goes wrong, you'll want a record of what data came in and when. Good logging makes troubleshooting dramatically easier.

Plan for failures. Your receiving system might be down when a webhook fires. Choose webhook providers that retry failed deliveries, and build your system to recover gracefully from missed events.

FAQs

Do webhooks work in real-time?
Nearly. Webhooks fire within moments of the triggering event and deliver data in seconds. For practical purposes, they're real-time.

What format does webhook data use?
Most webhooks send data as JSON, though some use XML or form-encoded formats. Check your specific integration's documentation for details.

What happens if my server is down when a webhook fires?
Most webhook providers retry failed deliveries several times over a period of hours or days. If all retries fail, the data may be lost unless you have other recovery mechanisms in place.

Can I test webhooks before going live?
Yes. Tools like RequestBin let you create temporary URLs to inspect incoming webhook data. Many platforms also offer test modes that simulate webhook deliveries.

Ready to connect your apps and automate your workflows? Start your free ActiveCampaign trial and see how webhooks can keep your systems in sync.