Why Were Webhooks Introduced?
Before diving into the concept of webhooks, let’s explore some foundational terms to understand why webhooks are important, how they differ from APIs, and the problems they solve.
What is an API?
An API (Application Programming Interface) is a way for a client (like a frontend app) and server (like a backend service) to communicate using the HTTP protocol. The client sends an HTTP request to the server, and the server responds—usually with data in JSON or XML format.
📘 Want to know more about APIs? Check this out: API Docs
What is Polling?
Sometimes, servers can’t immediately respond with data because they need to run complex algorithms or perform background processing that takes time. A simple HTTP request may timeout in such cases, especially when real-time feedback is needed (e.g., status updates or background job completions).
To solve this, polling was introduced.
Polling is the process where the client repeatedly sends requests to the server at fixed intervals to check whether new data is available or a specific event has occurred. This keeps the client in sync with backend state changes over time.
Think of polling as the client asking: “Is it ready yet? …How about now?”
While polling works, it isn’t always efficient. For example, consider an online payment system—polling the payment status endpoint every few seconds wastes bandwidth, increases server load, and isn’t scalable.
That’s where webhooks come in.
What is a Webhook?
A webhook is a lightweight, event-driven HTTP callback that allows the server to push data to the client, rather than the client pulling it continuously.
In simple terms:
A webhook is the server saying, „Hey! That thing you care about just happened. Here’s the data!“
Webhooks are often called reverse APIs or push APIs because they shift the responsibility of making the request from the client to the server. Instead of polling an API endpoint over and over, the server automatically sends an HTTP POST request to a URL you (the client) specify—only when a specific event occurs.
For example, in a payment system, you can register a webhook URL for payment_success. Once the payment is processed, the server will automatically send a POST request with the payment details to your webhook URL.
See this diagram :
How Do Webhooks Work?
- The client registers a webhook URL with the server.
- The client specifies the event(s) it wants to listen to (e.g., „order placed“, „payment successful“).
- The server stores this webhook configuration.
- When the event occurs, the server sends a POST request with the payload (data) to the client’s webhook URL.
Webhook vs API – What’s the Difference?
| Feature | API (Pull) | Webhook (Push) |
|---|---|---|
| Trigger | Client sends requests | Server sends request on event |
| Direction | Pull from server | Push to client |
| Efficiency | Less efficient (polling needed) | More efficient (event-based) |
| Use case | General data fetching | Real-time event notifications |
Benefits of Using Webhooks
Real-time updates
No more waiting or polling for updates. Get notified the moment something happens.
Reduced server load
No repeated API calls. Saves bandwidth and computing resources on both sides.
Simple and lightweight
Only one request is made—when it’s actually needed.
Event-driven design
Makes your app more responsive, especially for workflows involving third-party services like Stripe, Razorpay, or GitHub.
Better user experience
End users don’t have to refresh or wait unnecessarily to see changes.
Summary
Webhooks are a powerful mechanism to build real-time, responsive systems. They help reduce overhead, improve scalability, and deliver faster feedback loops in modern web applications.
Whether you’re building a payment system, integrating with external APIs, or handling background jobs, webhooks are a smart solution for triggering actions based on events.