2026-03-07 14:51 Tags:Technical Literacy

One sentence to remember

API:

“Let me check if something happened.”

Webhook:

“I’ll tell you when something happens.”

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1. First: normal API communication

A normal API works like asking a question.

Client → Server

Example:

GET /orders/123

You are asking:

“Do you have data for order 123?”

The server replies.

So the pattern is:

Client asks → Server responds

This is called request–response.

Example services using this pattern:

• Stripe API

• Reddit API

• Notion API

You ask for data when you want it.

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2. The problem with APIs for events

Imagine you run a payment system.

You want to know:

“When did a customer pay?”

If you only use APIs, you must keep asking.

Example:

GET /payments
GET /payments
GET /payments
GET /payments

This is called polling.

You’re constantly asking the server:

“Anything new yet?”

Most requests return nothing.

This wastes resources.

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3. The webhook idea

A webhook flips the direction.

Instead of asking repeatedly, you say:

“When something happens, notify me.”

Example:

Stripe → your server

When a payment happens:

Stripe sends:

POST /webhook/payment

Payload:

{
 "event": "payment_success",
 "amount": 2000,
 "customer": "cus_123"
}

Your server receives it instantly.

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4. The key difference

Normal API

You pull data.

Client → request → Server

Example:

GET /payments

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Webhook

The server pushes data.

Server → notification → Client

Example:

POST /webhook/payment

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5. Why the article calls webhooks “reverse APIs”

Because the direction flips.

Normal API:

You → server

Webhook:

Server → you

That’s why people say:

push vs pull

Pattern	Who initiates
API	client pulls data
Webhook	server pushes data

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6. Real-world example

Let’s use
Stripe again.

When a payment succeeds, Stripe sends a webhook.

Example event:

payment_intent.succeeded

Stripe automatically sends:

POST https://yourapp.com/webhook

With the payment data.

Your system can then:

• update the order

• send a receipt

• unlock content

All automatically.

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7. Another example: GitHub

The platform
GitHub
uses webhooks for automation.

When someone pushes code:

push event

GitHub sends a webhook to a CI CD CI/CD system.

Example workflow:

GitHub → webhook → build server

Then:

• tests run

• deployment starts

This is how continuous deployment works.

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8. Why webhooks are perfect for automation

Because they are event-driven.

Something happens → automation runs.

Example:

Payment received
      ↓
Webhook
      ↓
Send email
      ↓
Update database

Tools like n8n rely heavily on this pattern.

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9. The important line in the text

“An application must have an API to use a webhook.”

This means:

Webhooks don’t replace APIs.

They work with them.

Example flow:

Stripe webhook → your server
           ↓
Your server calls Stripe API
           ↓
GET /payment_details

The webhook tells you something happened.

The API lets you fetch full data.

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10. A simple mental model

Think of APIs and webhooks like communication styles.

API:

You call someone to ask for information

Webhook:

Someone calls you when something happens

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11. Why this matters for your automation work

If you build systems like:

Reddit → n8n → Notion

Right now you’re probably using API polling.

Example:

Check Reddit every hour

But some systems use webhooks:

New event → trigger automation

This is much more efficient.

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