I once built a tiny script that checked a service every minute.

“Any new orders?”

No.

One minute later:

“Any new orders?”

No.

Again.

The script worked. It was also ridiculous.

Most of the day, nothing happened. The software kept asking anyway, creating unnecessary requests, logs and opportunities to fail.

Then I learned to use a webhook.

Instead of repeatedly checking for changes, my application gave the other service an address and said, roughly, “Tell me when something happens.”

That small shift makes integrations feel much more natural.

The internet has enough software asking questions already.

Sometimes the useful thing is to wait for a call.

Polling is simple, which is why people use it

Polling means checking another system on a schedule.

Every minute, every five minutes, every hour.

It is easy to understand and often perfectly acceptable.

A dashboard might refresh data every few minutes. A nightly reporting job can check for completed transactions. If timing is not important and the API is cheap to query, polling may be the simplest solution.

The trouble comes when you want immediate updates.

Check every hour and the user waits too long. Check every second and you waste resources.

Webhooks solve that timing problem elegantly.

The source system sends an HTTP request to your application when the event occurs.

New payment.

New GitHub push.

New form submission.

No constant checking required.

The endpoint becomes a doorbell

A webhook endpoint is basically a web address designed to receive event messages.

You register that address with the service sending events.

When something happens, it posts data to your endpoint.

Your application then decides what to do.

A payment provider says the transaction succeeded. Your system marks the order paid and sends confirmation. A code repository reports a new push. Your automation starts tests. A form tool reports a new response. The CRM creates a lead.

This is why webhooks appear everywhere in automation platforms.

They turn software into reactions.

Something happens here.

Do something there.

“Delivered” does not mean “processed”

This distinction causes trouble.

The sending service may successfully deliver a webhook to your server.

Your application then fails while processing it.

Maybe the database is down. Maybe the payload contains an unexpected value. Maybe the email service times out.

From the sender’s perspective, delivery worked.

From the business perspective, the order is still not updated.

Good webhook systems separate receiving from processing.

Accept the event quickly, store it safely or put it on a queue, then perform slower work afterward.

That way a temporary downstream problem does not make the sender wait or retry unnecessarily.

Fast acknowledgements keep integrations calmer.

Retries are a feature and a danger

Webhooks travel over networks.

Networks fail.

The receiver may be offline for a moment. A request may time out. Many providers retry webhook delivery when they do not receive a successful response.

Excellent.

Now imagine your application receives the same “payment completed” event twice and processes it twice.

Maybe two confirmation emails are sent.

Maybe inventory is reduced twice.

Maybe something more expensive happens.

Webhook handlers should be idempotent when possible, meaning processing the same event more than once does not create duplicate effects.

A unique event ID helps.

Store which events have already been processed.

Distributed systems repeat themselves.

Design for it.

Security cannot rely on a secret-looking URL

Webhook endpoints are often public because external services need to reach them.

Do not assume nobody will discover the address.

An attacker could send fake requests and try to trigger actions inside your system.

Reputable services usually provide a way to verify that webhook messages genuinely came from them, often using cryptographic signatures based on a shared secret.

Use it.

Check timestamps where supported to reduce replay attacks. Validate the payload. Reject events you did not subscribe to.

A webhook can trigger meaningful business actions.

Treat it like an API endpoint, not a mailbox on the porch.

Debugging webhooks is weirdly satisfying

The first problem is visibility.

A user says the order was paid, but your application never updated.

Did the provider send the webhook? Did your server receive it? What status code did you return? Did processing fail later?

Good providers offer delivery logs and replay tools. Your application should log event IDs and processing outcomes.

In development, tools can expose a temporary public endpoint so you can inspect incoming requests locally.

Once you can see the event, debugging becomes much easier.

Without visibility, webhook problems turn into two teams looking at each other and saying, “It worked on our side.”

A timeless integration tradition.

Order is not guaranteed

Events can arrive late.

They can arrive out of order.

A “subscription cancelled” webhook might reach you before an earlier “subscription updated” event because the network took different paths or one delivery was retried.

If your system blindly applies events in arrival order, state can move backwards.

Use event timestamps or version numbers when the provider supplies them. Fetch the latest state from the source system for critical workflows rather than trusting every event to represent current truth.

A webhook tells you something happened.

It does not always tell you that nothing else happened afterward.

Webhooks reduce work, not responsibility

Developers sometimes describe webhooks as “fire and forget.”

I dislike that phrase.

The sender may fire.

The receiver should remember.

Events need monitoring, retry policies and dead-letter handling for failures that cannot be processed immediately. Critical events may need reconciliation jobs that compare your data with the source periodically.

Yes, periodic checking returns.

The difference is that polling becomes a safety net rather than the primary mechanism.

Real systems like belts and suspenders.

Especially around money.

They are excellent for no-code automation too

You do not have to be building a large software platform to use webhooks.

Automation tools let people connect services through simple triggers.

A website form can notify a workflow. An e-commerce event can update a spreadsheet. An internal system can call a webhook to start a chain of tasks.

This gives non-developers access to event-driven thinking.

The risk is that workflows become invisible.

Six months later, nobody remembers why a customer email sends twice.

Document important automations. Name them clearly. Know which account owns them.

No-code still creates systems.

Systems need owners.

I still use polling sometimes

Webhooks are not automatically better.

If the source service does not offer them, polling is fine. If you only need a daily update, a scheduled check may be simpler. If missing one webhook would be catastrophic, you may want periodic reconciliation anyway.

The choice depends on urgency, reliability and complexity.

I use webhooks when the event matters quickly and the provider supports them well.

I use polling when delay is acceptable and simplicity wins.

The useful lesson is not “webhooks good.”

It is that software does not always need to keep asking whether something happened.

Sometimes it can wait for the doorbell.