Webhooks Explained: How Your Tools Actually Talk to Each Other

A client asked me recently, "how does our website even know when a payment goes through in Stripe." The answer, most of the time, is a webhook, and it's worth understanding even if you never write a line of code yourself, because it's quietly running a lot of your business.

What a webhook actually is, in plain terms

Most of the time, when one piece of software needs information from another, it has to ask: "hey, has anything new happened?" over and over, on a schedule. That's called polling, and it's slow and wasteful, like calling a friend every five minutes to ask if they've texted you back.

A webhook flips that around. Instead of asking repeatedly, you give the other system a specific web address and say "the moment something happens, send the details here, immediately." When a customer completes checkout on Shopify, Shopify doesn't wait to be asked, it immediately sends a message to whatever address you've configured, saying "here's what just happened, and here's the data."

That's it. That's the whole concept. A notification, sent instantly, the moment an event occurs, instead of you having to go check.

Where you're probably already using them

A new order in your store triggering an email in your marketing tool. A new form submission on your site creating a lead in your CRM. A payment succeeding in Stripe updating an order's status on your website. A new signup in one tool adding a contact to another. All of these, under the hood, are almost always webhooks doing the actual connecting work, often through a no-code tool like Zapier or Make sitting in between.

Why they break, and what to actually check

Webhooks are simple in concept and fragile in practice, for a few specific reasons worth knowing even if you're not the one debugging them.

The receiving address changes. If your website gets rebuilt or moves hosting, and the webhook URL configured in Stripe or Shopify still points to the old address, those notifications silently go nowhere. "Silently" is the dangerous part, there's often no obvious error, orders just stop syncing and nobody notices until a customer complains.

Authentication gets out of sync. Most webhooks include a secret key or signature so the receiving system can confirm the message is legitimate and not spoofed. If that key changes on one side and not the other, the webhook can fail security checks and get silently rejected.

The receiving system goes down, even briefly. If your website is down for thirty seconds during a deploy and a webhook fires during that window, some services retry automatically, and some don't. Know which behavior your tools have, because it decides whether a missed event is recoverable or just lost.

The one habit that prevents most webhook problems

Log every webhook you receive, even just the basics, timestamp and event type, somewhere you can actually check later. When a customer says "I paid but my order shows unpaid," a webhook log turns a mystery into a five-minute lookup: did we receive the payment webhook, did we process it correctly, or did it never arrive at all. Without that log, you're guessing, and guessing with a customer's money involved is a bad position to be in.

What to ask, if someone else built this for you

Which business processes actually depend on a webhook right now? What happens if one fails silently, is there any alerting, or would you only find out from a customer complaint? Those two questions alone reveal whether your automation is solid or just working by accident so far. Worth asking before it's the thing that breaks during your busiest week.