Webhooks Explained: Shopify, Zapier, Slack & Discord Automation Made Simple (2026 Guide)

Webhooks is that one thing which I think a lot of people should know about, but they don’t. Most people just copy-paste code to accept a webhook call from a provider and move on. But that approach usually comes back to bite you later.

So in this blog, I want to talk a little bit about webhooks properly — what a webhook is, how you can create one, the process involved, and how it should ideally work in real-world applications.

If you have ever worked with payments, automation tools, or third-party services, chances are you’re already using webhooks — whether you fully understand them or not.

Where Do We See Webhooks in Real Life?

If you have ever accepted payments from Stripe, Razorpay, or any payment gateway, you already know that there is a concept of webhooks.

Payment systems are usually the first example that comes to mind because they use webhooks extensively. But webhooks are everywhere.You will find webhooks in:

Pretty much anywhere your service needs to coordinate with an external service, webhooks are involved.

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What Is a Webhook? (Simple Explanation)

In very simple terms, imagine this:

This is your server (maybe an EC2 instance you own).
This is an external company like Stripe.

You tell Stripe something like:

“Hey Stripe, can you send a request to my server when something happens on your side?”

That “something” is called a webhook event.

Instead of your server constantly asking Stripe,

“Did something happen yet?”

Stripe tells you directly when it happens.

A Real Example: Payment Webhooks in Action

Let’s take a real-world scenario.

At CodeDam, when someone buys:

a pro subscription
a full-stack learning path
any course or learning path

They land on the Stripe checkout page.

On that page, they enter:

card details
name
address
and then click the Pay button

When the transaction is successful, Stripe, under the hood, sends a webhook request to our backend.

In our case:

That backend is a Lambda
It powers our GraphQL API

Stripe basically tells us:

“Hey, someone has paid for this service.”

Along with that request, Stripe also sends metadata.

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What Happens on the Backend?

On our backend, we:

Receive the webhook request
Decode the metadata
Identify which user made the payment
Add the subscription to their account

All of this happens in a matter of seconds.

From the user’s point of view:

They click the payment button
Stripe validates the card
Charges the amount
Sends the webhook
Backend processes it
The user instantly gets access to their pro account

This is the real power of webhooks.

Why You Should Never Rely Only on the Frontend

You might ask:

“Stripe redirects the user back to my website with a payment ID. Can’t I just verify the transaction there?”

Sure, you can. But a lot can go wrong.

For example:

The electricity at the user’s house goes off
The browser tab is accidentally closed
Internet stops working
Your frontend crashes
Your website temporarily goes down

In all of these cases, the payment may still succeed, but your frontend never reports it.

That’s where webhooks become critical.

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Even if the user never returns to your website, Stripe still sends a webhook to your server saying:

“Payment successful.”

That makes webhooks far more reliable than client-side callbacks.

Webhooks Are Not Always User-Triggered

Another important thing people miss is that not all webhook events come from direct user actions.

For example, you might configure Stripe like this:

“Tell me whenever a subscription is canceled.”

Now, this cancellation can happen in different ways.

Synchronous Webhook Example

A synchronous case is when:

A user goes to their dashboard
Opens settings
Clicks Cancel Subscription

That action immediately triggers a webhook.

Asynchronous Webhook Example

But what if:

A card expires?
A recurring payment fails?
A subscription is automatically canceled by Stripe?

There is no user interaction here.

Still, Stripe sends a webhook to inform your system.

That’s why relying only on frontend logic is dangerous.

An asynchronous way is when your recurring payment fails. In that case, Stripe would automatically call the webhook for us and update our backend that:

“Hey, your pro membership is over.”

Maybe after that, we send the user some information over email, and so on.

This is important because here, no user action is involved.
The user didn’t click any button.
The frontend didn’t send anything.

Yet, your backend still needs to know what happened — and that only works because of webhooks.

The Most Critical Question: How Do We Trust a Webhook?

Now, a very important part here — a very, very critical part — is this:

👉 How does your backend know that this request is actually coming from Stripe and not from an attacker or someone else?

This is where webhooks start getting interesting.

Webhook Security: The Signing Secret

Let’s say this is Stripe, and this is your server.

The first thing that happens is:

You give Stripe a secret, or
Stripe gives you a secret

You’ll find this inside the provider’s dashboard.

This secret is called a signing secret.

HTTPS Is Not Enough

Yes, the webhook request is sent over HTTPS.
That is the first level of security.

But HTTPS alone is not enough.

The second level of security is verifying that:

“This message was actually sent by Stripe.”

How Signature Verification Works (In Simple Terms)

What Stripe does is this:

Stripe takes the webhook payload (the message)
Stripe hashes that message
Stripe uses your signing secret while hashing
Stripe sends:
- the webhook payload
- plus a signature header (usually something like X-Signature or Stripe-Signature)

Now, on your backend:

You take the webhook body
You hash it again using the same secret
You compare your generated hash with the signature Stripe sent

If they match → ✅ request is valid
If they don’t → ❌ reject the request

What Is a Hash (Quick Intuition)

We’ve talked about hashes before — things like MD5 and SHA-1.

A simple way to think about a hash is:

It’s a one-way transformation of data
Even a single bit change in the data completely changes the hash
For example:
- Hash a 2 MB file
- You get a fixed-length string (like 32 characters in MD5)
- If anything changes in the file, the hash changes entirely

That’s why hashes are used for integrity verification.

You don’t need to compare the entire file — just compare the hash.

Why the Signing Secret Matters So Much

Stripe hashes the message using your secret key.

Why is that important?

Because:

Only Stripe and you know that secret
An attacker does not

So even if someone:

Finds your webhook URL
Sends fake requests
Tries to grant themselves a pro account

They cannot generate a valid signature.

And your backend will reject the request.

What Happens If You Skip Signature Verification?

This is probably the biggest mistake people make.

If this verification does not exist:

Anyone who discovers your webhook URL
Can send fake requests
Can grant subscriptions
Can cancel accounts
Can completely break your system

If your service becomes popular, trust me:

It’s just a matter of time before someone finds that endpoint and starts abusing it.

What a Proper Webhook Setup Looks Like

A proper webhook implementation should always have:

Event-based triggering
- Synchronous (user actions)
- Asynchronous (system events)
Secure verification
- HTTPS
- Signature validation using a signing secret

This is how:

Stripe works
Razorpay works
Shopify webhook systems work
GitHub, Slack, Discord, and Zapier webhooks work

This is how good webhooks should always work.

Webhook Reliability: Retries and Exponential Backoff

If you sign the message, if it is delivered over HTTPS, and if you have the correct webhook URLs set up, webhooks become a very powerful and reliable way to listen for important events.

There is one more important thing that good webhook providers support — automatic retries.

Let’s say your webhook endpoint responds with:

400 (bad request)
404 (not found)
502 or 503 (server error)

In simple terms, anything greater than or equal to 400.

In that case, the webhook provider understands that something went wrong on your server, and instead of giving up, it tries again.

How Webhook Retries Work (Exponential Backoff)

Providers like Stripe retry webhook calls using an exponential backoff algorithm.

You don’t need to know the math — just the idea.

It works like this:

First retry → after 1 second
Second retry → after 2 seconds
Third retry → after 4 seconds
Then 8 seconds, 16 seconds, and so on

The delay keeps increasing exponentially.

Why?

Because Stripe does not want to:

bombard your server
overload it further
make a bad situation worse

So it retries slowly and intelligently.

This is more on the reliability side, but it’s a very nice feature to have in a webhook system.

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What Really Matters in a Webhook System

Retries are great, but the core of webhooks is still this:

Security
- HTTPS
- Signed payload verification
Events
- Clear event types
- Proper dispatching to the right endpoints

Once you have these two things, you already have a solid webhook system.

Why Webhooks Exist (The Big Picture)

Now, when you implement a webhook, you know:

Why you need it → because clients are unreliable
Why verification is mandatory → because security matters
How it works internally → not magic, just servers talking securely

Even if you are building your own webhook system, the idea is simple:

Allow people to create events
Store webhook endpoints
Use a cron job, event system, or queue
Dispatch webhook requests periodically
Retry failed deliveries safely

That’s it.

Final Thoughts

If you’ve worked with payments, you probably already knew some of this.
But taking time to understand these concepts deeply and separately is always worth it.

Webhooks are simple in theory, but critical in production systems.

Once you understand them properly, you stop copy-pasting code — and start designing systems that are:

secure
reliable
scalable

That’s pretty much it for this one.