# API vs Webhook

URL: https://softwaredictionary.org/compare/api-vs-webhook
Last updated: 2026-10-06

In short: With an API, your app sends a request whenever it wants data; with a webhook, another service sends a request to your URL as soon as an event happens.

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

An API is the set of operations a service offers: your application calls it whenever it needs something, such as reading an order or creating a payment, and gets a response right away. A webhook turns the direction around. You give a service a URL, and when an event you care about happens, such as a successful payment or a push to a repository, the service sends an HTTP `POST` to that URL with the details.

That is why webhooks are sometimes called reverse APIs. With an API alone, learning about changes means polling: asking again and again whether anything is new, which wastes requests and delays the news by up to the polling interval. A webhook delivers the event within seconds, and only when there is something to say.

They are partners more than alternatives. The URL you register for a webhook is in fact a small API endpoint of your own, which the other service calls, and most services offer both: webhooks to announce that something happened, and an API to fetch the full details or act on them. A typical handler receives a webhook, checks it, and then calls the sender's API for the latest state.

Webhooks bring their own duties. Because the URL is public, the receiver must verify each delivery, usually through a signature made with a shared secret. Senders retry failed deliveries, so the same event can arrive twice or out of order, and the handler should answer quickly with a `2xx` status and do the real work in the background.

| Aspect | API | Webhook |
| --- | --- | --- |
| Direction | Your app calls the service | The service calls your app |
| Trigger | Your code decides when to ask | An event in the other system |
| Timing | Whenever you ask; noticing changes needs polling | Within seconds of the event |
| What you provide | An API key or token with each request | A public URL that accepts `POST` requests |
| Data | Whatever you request: read, create, update or delete | A notification describing one event |
| Failure handling | You see the error in the response and can retry | The sender retries; you must handle duplicates |
| Security | The service authenticates you | You verify the sender, usually by a signature |
| Typical use | Reading and changing data on demand | Payment confirmations, Git pushes, form submissions |

## Choose API when

- Your app needs data or must take an action at a moment it chooses.
- You need the full, current state of something, not just a notice that it changed.
- Your app can't expose a public URL, such as a mobile app or a script behind a firewall.

## Choose Webhook when

- You need to react quickly when something happens in another system.
- Polling would waste requests or run into rate limits.
- You can run a public, secured endpoint that handles retries and duplicates.

## Frequently asked questions

**Is a webhook an API?**

In a sense. A webhook is an HTTP request one system sends to an endpoint of another, so the receiving URL is a tiny API. The difference is who starts the call: with a webhook, the provider does.

**Webhook or polling: which is better?**

Webhooks give timely updates with fewer requests; polling works when you can't receive incoming requests or need a simple fallback. Many integrations combine them, polling now and then to catch any missed webhook.

**How do I secure a webhook endpoint?**

Use HTTPS, verify the signature header with the shared secret, reject old timestamps to stop replays, and make the handler idempotent so a repeated event does no harm.

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Software Dictionary: https://softwaredictionary.org/ · https://softwaredictionary.org/llms.txt