What Is a Webhook? A Simple Explanation With Real Examples

A webhook is a way for one system to notify another system the moment something happens, without being asked. Instead of your system repeatedly checking "did anything change yet?", the other system sends you a message when the event occurs. It is push, not pull.

The doorbell framing

Think about how you know when a visitor arrives at your gate.

Without a doorbell (polling): You walk to the gate every five minutes, open it, look outside, and check if anyone is there. Most of the time, nobody is. You wasted the trip. But you keep checking because you do not want to miss anyone. This is exhausting and inefficient.

With a doorbell (webhook): You go about your business inside the house. When a visitor arrives, they press the doorbell. You hear the ring and go to the gate. You only respond when there is actually someone there.

A webhook works exactly like the doorbell. Your system sits idle, doing other things. When an event happens on another system, that system "rings the bell" by sending a message to a URL you provided. Your system receives the message and acts on it.

The difference in efficiency is significant. Polling wastes resources checking for events that usually have not happened. Webhooks deliver information only when there is something to deliver.

A real example: M-Pesa payment notification

Let us trace a concrete payment scenario that many Kenyan businesses deal with.

A customer buys a product on your online store and pays via M-Pesa through Paystack. Your store needs to know when the payment succeeds so it can confirm the order and send the customer a receipt.

Without a webhook, your store would need to keep asking Paystack: "Has this payment been completed? How about now? Now?" That means sending a request every few seconds, consuming bandwidth and processing power, and still potentially missing the exact moment the payment clears.

With a webhook, you told Paystack during setup: "When a payment completes, send a notification to this URL on my server." Paystack stores that URL. When the customer finishes paying, Paystack immediately sends a message (the webhook) to your URL containing the payment details: amount, transaction ID, customer reference, and status.

Your server receives that message, verifies it is genuinely from Paystack (not someone faking a payment notification), updates the order status to "paid," and triggers a confirmation email to the customer. All of this happens within seconds of the payment completing.

That notification from Paystack to your server is the webhook. It is a single HTTP request, pushed from Paystack to you, containing structured data about an event that just occurred.

What data does a webhook contain?

A webhook payload (the data it carries) depends on the service sending it and the event that triggered it. For a payment webhook, you typically receive the transaction amount and currency, a unique transaction identifier, the payment method used, whether it succeeded or failed, a timestamp, and any reference information you attached when creating the payment.

The data arrives in a structured format (usually JSON) that your system can read and process automatically. You do not parse a human-readable email. You receive machine-readable data that your software can act on immediately.

Where you encounter webhooks beyond payments

Webhooks are everywhere in modern software, even if the term is hidden from view.

Form submissions. When someone fills out a Typeform, the platform can send a webhook to your automation tool with all the form data. That is how tools like Zapier and Make receive data from forms in real time.

Messaging platforms. When a customer sends a message to your WhatsApp Business number through the API, WhatsApp sends a webhook to your server with the message content. Your chatbot system receives this webhook and responds.

E-commerce platforms. When an order is placed, shipped, or delivered, platforms like WooCommerce and Shopify send webhooks to connected systems. That is how inventory management tools update stock counts instantly.

Version control. When a developer pushes code to GitHub, a webhook can notify the deployment system to update the live website. This is how many websites update automatically when new content is published.

The pattern is always the same: an event happens on System A, and System A immediately notifies System B by sending data to a pre-configured URL.

Webhooks versus APIs

People often confuse webhooks with APIs. The distinction is about direction.

An API call is pull-based. Your system sends a request to another system and gets a response back. You initiate the conversation. "Give me the current exchange rate." The API responds with the rate.

A webhook is push-based. Another system sends data to your system when an event happens. They initiate the conversation. "A payment just completed, here are the details."

Many integrations use both. You call the Paystack API to create a payment (pull). Paystack sends you a webhook when the payment completes (push). The API handles your requests. The webhook handles their notifications.

Understanding this distinction helps when you are building automation workflows. Webhooks are often the trigger that starts a workflow. "When I receive a webhook from Paystack confirming payment, run this sequence of actions." The trigger-action-condition model that underlies all workflow automation frequently starts with a webhook.

Security: verifying webhooks

Because webhooks involve receiving data from external systems, security matters. If your system blindly trusts every incoming webhook, someone could fake a payment notification and trick your store into confirming an order that was never paid for.

Reputable services like Paystack include a signature with each webhook. This is a cryptographic code generated using a secret key that only you and the sender know. Your system recalculates the signature using the same key and compares it to the one in the webhook. If they match, the webhook is genuine. If not, it is rejected.

This verification step is not optional. Any system that processes webhooks related to payments, user data, or access control must verify the sender's identity.

Getting started with webhooks

If you use a no-code platform like Zapier or Make, you are already using webhooks, even if the platform calls them "instant triggers" or "real-time events." When you set up a Zap that fires instantly when a form is submitted, the form service is sending a webhook to Zapier behind the scenes.

For a practical introduction to how webhooks fit into larger AI and automation workflows, our free welcome module covers the fundamentals you need, connecting concepts like webhooks, AI, and automation into practical skills.

FAQ

Do I need to know how to code to use webhooks?

Not if you use no-code platforms. Zapier, Make, and n8n handle webhook reception and processing through visual interfaces. You configure a "webhook trigger" by copying a URL into the sending service's settings. The platform handles receiving the data and letting you use it in your workflow. If you want to build custom webhook receivers on your own server, basic programming knowledge is needed.

What happens if my system is offline when a webhook is sent?

Most webhook senders retry delivery several times over a period of hours or days. Paystack, for example, retries failed webhook deliveries. If all retries fail, the notification is lost, which is why critical systems also include a manual verification option. You can call the sender's API to check a transaction's status as a fallback if the webhook never arrives.

Can I test webhooks without building a full system?

Yes. Tools like Webhook.site and RequestBin give you a temporary URL that captures incoming webhooks and displays the data in your browser. You can configure a service to send test webhooks to that URL and see exactly what data arrives. This is an excellent way to understand webhook payloads before building anything that processes them.