What is the main difference between an API and a webhook?

The main difference lies in how data transfer is initiated between systems. An Application Programming Interface (API) requires a client to make a request to pull data from a server. Conversely, a webhook automatically pushes data from the server to the client immediately after a specific event happens, eliminating periodic polling requests.

Are webhooks secure for transmitting sensitive data?

Webhooks are secure when proper encryption and authentication mechanisms are implemented. Senders typically encrypt transmissions using Hypertext Transfer Protocol Secure (HTTPS) and include a cryptographic signature in the header. Receivers verify this signature using a shared secret key to confirm the payload came from an authentic source without modification.

What happens if a webhook fails to deliver data?

If a receiving endpoint is offline, most webhook providers automatically retry delivery using an exponential backoff strategy. The sending system logs delivery failures and periodically attempts retransmission over a defined period. If the destination continues to fail, the webhook sender usually disables the endpoint and sends an alert.

Web Development

Webhook

A webhook is an automated message sent from one application to another as soon as an event occurs, eliminating the need to continuously check for updates.

also called: webhooks

// definition

A webhook is an automated Hypertext Transfer Protocol (HTTP) POST request sent by a source application to a target destination URL when a predefined event takes place. The payload is commonly formatted in JavaScript Object Notation (JSON) and contains detailed data regarding the trigger event. Because communication originates from the sender upon event occurrence, webhooks function as event-driven callbacks across distributed software systems.

Webhooks are often confused with standard Application Programming Interface (API) requests. While traditional API calls require a receiving system to make repeated polling requests to check for new data, webhooks automatically push data to the receiver instantly. This shift from pull-based polling to push-based notification significantly reduces unnecessary network traffic and latency.

// why it matters

Implementing webhooks allows business applications to exchange information instantaneously without continuous server requests. This reduces server bandwidth requirements and processing costs associated with database polling. Real-time data delivery ensures downstream operations, such as order fulfillment or account provisioning, trigger immediately when an event completes. System reliability improves because services process updates only when changes actually occur, eliminating thousands of redundant status checks throughout the day.

// example

When a customer successfully pays an invoice on an e-commerce platform, the payment gateway creates an event and transmits a JSON payload to the store application's webhook URL. The message contains transaction details including payment status and order reference. Upon receiving this payload, the store server verifies the digital signature and automatically updates the order status to paid, triggering an automated email notification to the customer.

Questions and Answers

What is the main difference between an API and a webhook?: The main difference lies in how data transfer is initiated between systems. An Application Programming Interface (API) requires a client to make a request to pull data from a server. Conversely, a webhook automatically pushes data from the server to the client immediately after a specific event happens, eliminating periodic polling requests.
Are webhooks secure for transmitting sensitive data?: Webhooks are secure when proper encryption and authentication mechanisms are implemented. Senders typically encrypt transmissions using Hypertext Transfer Protocol Secure (HTTPS) and include a cryptographic signature in the header. Receivers verify this signature using a shared secret key to confirm the payload came from an authentic source without modification.
What happens if a webhook fails to deliver data?: If a receiving endpoint is offline, most webhook providers automatically retry delivery using an exponential backoff strategy. The sending system logs delivery failures and periodically attempts retransmission over a defined period. If the destination continues to fail, the webhook sender usually disables the endpoint and sends an alert.