What is a Webhook?#
A webhook is a mechanism that allows real-time communication between two systems by sending an HTTP request (usually a POST request) from one application to another when a specific event occurs. Unlike traditional polling, where a system repeatedly checks for updates, webhooks push data automatically, reducing latency and improving efficiency.In simple terms, webhooks act as event-driven notifications that alert an external system when something happens.
How Webhooks Work#
1.
Event Trigger – A specific event occurs in the source system (e.g., a bank transaction is processed).
2.
Webhook URL – The system that needs to be notified (the receiver) provides a URL where the event data should be sent.
3.
HTTP Request – The source system sends an HTTP POST request to the webhook URL, containing the event details in JSON or XML format.
4.
Processing the Data – The receiving system extracts and processes the event data, taking appropriate action (e.g., updating records, notifying customers).
5.
Acknowledgment & Retry Mechanism – The receiver responds with an HTTP status code (200 OK for success). If the request fails, the sender may retry to ensure reliable delivery.
Example of a Webhook Flow in Banking#
Scenario: A Real-Time Payment Notification Webhook#
Imagine a bank provides an API that allows businesses to receive real-time notifications when a customer makes a payment.1.
A merchant registers a webhook URL with the bank’s API to receive payment updates.Example: https://merchant.com/webhook/payment
2.
A customer makes a payment, and the bank’s system processes the transaction.
3.
The bank’s system triggers a webhook event for the payment success.
4.
An HTTP POST request is sent to the merchant's webhook URL with payment details:{
"event": "payment.success",
"transaction_id": "TXN123456789",
"amount": 5000,
"currency": "NGN",
"customer": {
"name": "John Doe",
"email": "john.doe@example.com"
},
"status": "successful",
"timestamp": "2025-04-03T14:30:00Z"
}
Webhook vs. API Polling: Why Webhooks Are Better?#
Webhooks and API polling are two different methods for retrieving data from a system, but webhooks are generally more efficient and preferred for real-time communication.1. Webhooks (Push Mechanism)#
Webhooks send data automatically when an event occurs.
No need for the client to continuously check for updates.
Uses minimal server resources and bandwidth.
2. API Polling (Pull Mechanism)#
The client must repeatedly send requests at intervals to check for updates.
Can cause high server load and increased bandwidth usage.
May lead to delays in receiving critical updates.
Comparison Table#
| Feature | Webhooks | API Polling |
|---|
| Data Delivery | Instant (push) | Delayed (pull) |
| Efficiency | High | Low |
| Server Load | Low | High (frequent requests) |
| Bandwidth Usage | Minimal | High |
| Real-time Updates | Yes | No |
| Reliability | Requires proper handling of retries | Can miss updates if polling interval is too long |
| Complexity | Requires webhook endpoint setup | Simpler but inefficient for frequent updates |
When to Use Webhooks vs. API Polling#
You need real-time notifications (e.g., transaction updates, payment confirmations).
You want to reduce server load and improve efficiency.
You are integrating with event-driven systems.
The system does not support webhooks.
You need historical data or scheduled updates (e.g., daily reports).
The update frequency is low and does not require real-time notifications.
Modified at 2025-04-03 21:21:17
