Why webhooks push notifications in Rest API - Visual Breakdown

Concept Flow - Why webhooks push notifications

Event Happens

↓

Webhook Server Detects Event

↓

Server Sends HTTP POST to Client URL

↓

Client Receives Notification

↓

Client Processes Data

↓

Client Responds with Status

↓

Server Logs Success or Retries on Failure

When an event occurs, the server immediately sends a notification to the client via HTTP POST, allowing real-time updates without the client asking repeatedly.

Execution Sample

Rest API

POST /webhook-endpoint HTTP/1.1
Host: client.example.com
Content-Type: application/json

{"event":"order_created","order_id":12345}

This shows the server pushing a notification to the client's webhook URL with event details.

Execution Table

Step	Action	Data Sent	Client Response	Server Reaction
1	Event occurs on server	N/A	N/A	Prepare webhook payload
2	Server sends POST request	{"event":"order_created","order_id":12345}	Waiting	Waiting for client response
3	Client receives POST	{"event":"order_created","order_id":12345}	200 OK	Logs success
4	Server logs success	N/A	N/A	No retry needed
5	If client fails to respond	N/A	Timeout or error	Retry or alert admin

💡 Notification process ends after client responds successfully or retries exhausted

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
event_detected	False	True	True	True
payload_sent	None	{"event":"order_created","order_id":12345}	{"event":"order_created","order_id":12345}	{"event":"order_created","order_id":12345}
client_response	None	Waiting	200 OK	200 OK
server_status	Idle	Sending	Success	Success

Key Moments - 3 Insights

Why does the server send data without the client asking?

Because webhooks push notifications automatically when events happen, so the client gets updates instantly without polling. See execution_table step 2.

What happens if the client does not respond?

The server waits for a response and may retry sending or alert an admin if it times out, as shown in execution_table step 5.

Why is the client’s response important?

The client’s response tells the server the notification was received successfully, so the server can stop retrying. See execution_table step 3.

Visual Quiz - 3 Questions

Look at the execution_table, what data does the server send at step 2?

A {"status":"waiting"}

B No data sent

C {"event":"order_created","order_id":12345}

D Client response data

💡 Hint

Check the 'Data Sent' column at step 2 in the execution_table

At which step does the server log a successful notification?

A Step 1

B Step 4

C Step 3

D Step 5

💡 Hint

Look at the 'Server Reaction' column for when success is logged

If the client never responds, what will the server do according to the table?

A Retry sending or alert admin

B Stop immediately

C Send a different event

D Ignore and continue

💡 Hint

See the last row in execution_table under 'Server Reaction'

Concept Snapshot

Webhooks push notifications by sending HTTP POST requests from server to client when events happen.
This avoids client polling and provides real-time updates.
Client must respond to confirm receipt.
Server retries if client fails to respond.
Used for instant communication between systems.

Full Transcript

Webhooks push notifications work by the server detecting an event and immediately sending an HTTP POST request to a client URL. This POST contains event data so the client knows what happened. The client receives this notification and processes it, then responds with a status code like 200 OK to confirm receipt. The server logs this success and stops retrying. If the client does not respond or returns an error, the server may retry sending or alert an administrator. This push method means the client does not have to keep asking the server for updates, saving resources and enabling real-time communication.

Practice

1. Why do webhooks push notifications instead of waiting for your app to ask for updates?

easy

A. To avoid sending any data to your app

B. To send updates instantly and save time and resources

C. To require your app to check for updates repeatedly

D. To make your app slower by adding delays

Solution

1. Step 1: Understand the purpose of webhooks

   Webhooks are designed to send data immediately when an event happens, instead of waiting for your app to ask.

2. Step 2: Compare push vs pull methods

   Push (webhooks) saves time and resources by sending updates instantly, unlike pull which requires repeated checking.

3. Final Answer:

   To send updates instantly and save time and resources -> Option B

4. Quick Check:

   Push notifications = instant updates [OK]

Hint: Webhooks push to save time and avoid repeated checks [OK]

Common Mistakes:

• Thinking webhooks slow down the app
• Confusing push with pull methods
• Believing webhooks avoid sending data

2. Which HTTP method do webhooks commonly use to send notifications?

easy

A. POST

B. DELETE

C. GET

D. PUT

Solution

1. Step 1: Identify the HTTP method for sending data

   Webhooks send event data to your app, which requires a method that can carry data in the request body.

2. Step 2: Match HTTP methods to their purpose

   POST is used to send data to a server, unlike GET which only requests data without sending a body.

3. Final Answer:

   POST -> Option A

4. Quick Check:

   Webhooks use POST to send data [OK]

Hint: Webhooks send data using POST requests [OK]

Common Mistakes:

• Choosing GET which only retrieves data
• Confusing PUT or DELETE with sending notifications
• Not knowing HTTP methods' purposes

3. Consider this webhook setup: Your app receives a POST request with event data immediately when a user updates their profile. What is the main benefit of this approach?

medium

A. Your app gets real-time updates without delay

B. Your app must ask repeatedly for updates

C. Your app ignores updates until manually refreshed

D. Your app receives outdated information

Solution

1. Step 1: Analyze the webhook behavior

   The webhook sends a POST request immediately when the event happens, so your app gets notified right away.

2. Step 2: Understand the benefit of instant notifications

   This means your app does not need to ask repeatedly and can update its data in real time.

3. Final Answer:

   Your app gets real-time updates without delay -> Option A

4. Quick Check:

   Instant POST = real-time updates [OK]

Hint: Instant POST means real-time updates [OK]

Common Mistakes:

• Thinking app must poll for updates
• Assuming updates are delayed
• Believing webhook sends outdated info

4. You set up a webhook but your app never receives notifications. Which of these is a likely cause?

medium

A. Your app is polling the webhook URL repeatedly

B. Your app is sending POST requests to the webhook

C. Webhooks use GET requests instead of POST

D. The webhook URL is incorrect or unreachable

Solution

1. Step 1: Check webhook delivery requirements

   Webhooks send POST requests to a URL your app provides. If the URL is wrong or unreachable, notifications won't arrive.

2. Step 2: Eliminate incorrect causes

   Your app does not send POST requests to the webhook; the webhook sends them. Webhooks use POST, not GET. Polling is unrelated to webhook delivery.

3. Final Answer:

   The webhook URL is incorrect or unreachable -> Option D

4. Quick Check:

   Wrong URL = no notifications [OK]

Hint: Check webhook URL correctness first [OK]

Common Mistakes:

• Thinking app sends POST to webhook
• Confusing HTTP methods used
• Assuming polling affects webhook delivery

5. You want your app to update user data immediately when a payment is completed. Which approach best uses webhooks to achieve this?

hard

A. Send GET requests from your app to the payment server repeatedly

B. Make your app check the payment status every minute

C. Set up a webhook that sends a POST notification to your app when payment completes

D. Ignore payment updates and refresh data manually

Solution

1. Step 1: Identify the goal

   You want immediate updates when payment completes, so your app must get notified instantly.

2. Step 2: Choose the webhook approach

   Setting up a webhook that sends a POST notification on payment completion pushes updates instantly, avoiding delays and repeated checks.

3. Final Answer:

   Set up a webhook that sends a POST notification to your app when payment completes -> Option C

4. Quick Check:

   Webhook POST = instant payment update [OK]

Hint: Use webhook POST for instant payment updates [OK]

Common Mistakes:

• Relying on polling instead of webhooks
• Using GET requests incorrectly
• Ignoring real-time update needs