Your Stripe Webhooks Aren't Firing: The Vibe Coder's Guide to Payment Integration

Here's the nightmare scenario: a customer pays you real money. You see the payment in your Stripe dashboard. But your app doesn't know about it. The customer didn't get access to what they paid for. They email you. You have no idea what happened.

This happens to almost every vibe-coded app that integrates payments. Here's why.

How payments actually work (the part the AI skips)

When someone pays through Stripe, there are actually TWO things that need to happen:

1. The payment. The customer enters their credit card, Stripe charges them, money moves. This part works because Stripe handles it entirely — the AI can't really mess it up.
2. The notification. After the payment succeeds, Stripe needs to tell YOUR app "hey, this person just paid." Your app then does something — unlocks a feature, marks an order as paid, sends a confirmation email. This is called a "webhook."

Step 1 almost always works. Step 2 is where everything falls apart.

What's a webhook, in plain English?

A webhook is a message. After something happens (like a payment), Stripe sends a message to a specific address on your app — something like yourapp.com/api/webhooks/stripe.

Your app receives the message, reads it, and does the right thing: "Oh, user X just paid. Let me give them access."

The problem is that this address, the code that receives the message, and the code that processes the message all have to be set up correctly. And they almost never are.

The five reasons your webhooks aren't working

1. The webhook URL points to localhost

This is the #1 problem. In development, the AI set the webhook to send messages to http://localhost:3000/api/webhook. That's your local computer. When you deploy to the real internet, Stripe is still trying to send messages to your laptop, which Stripe can't reach.

Fix: In your Stripe dashboard, go to Developers → Webhooks. Check where the webhook is pointing. It needs to be your real, deployed URL — not localhost.

2. You're using test mode keys in production (or vice versa)

Stripe has two sets of keys: test keys (start with sk_test_) and live keys (start with sk_live_). Test payments only fire test webhooks. Live payments only fire live webhooks. If your app has test keys but you're accepting real payments, the webhook never fires.

Fix: Check your environment variables. Make sure you're using sk_live_ keys in production. And make sure the webhook signing secret matches the mode you're using — test webhooks and live webhooks have different signing secrets.

3. The webhook signing secret is missing or wrong

When Stripe sends a webhook, it includes a signature — a way for your app to verify "this really came from Stripe and not someone pretending to be Stripe." Your app needs a signing secret to check this signature.

If the signing secret is wrong or missing, your app either rejects the webhook (security check fails) or accepts it but crashes trying to verify it.

Fix: In Stripe dashboard → Webhooks, click on your webhook endpoint. You'll see a "Signing secret" starting with whsec_. This needs to be in your app's environment variables as STRIPE_WEBHOOK_SECRET.

4. Your app isn't handling the webhook correctly

Even if Stripe sends the message and your app receives it, the code that processes the message might be broken. The AI might have written code that:

• Checks for the wrong event type (checking for payment_intent.succeeded when it should check checkout.session.completed)
• Crashes when it tries to update the database
• Doesn't send back the correct "I got your message" response, causing Stripe to think it failed

Fix: In Stripe dashboard → Webhooks → click your endpoint → "Attempts." This shows you every webhook Stripe tried to send. If you see red failures with error codes, that tells you what went wrong.

5. The AI replaced working code

This one is painful. You asked the AI to add a feature or fix a bug, and it rewrote your entire payment integration from scratch — breaking the webhook handling that was already working. The AI didn't understand the existing code well enough to modify it safely.

One documented case: a developer asked the AI to add a new payment tier. The AI replaced the entire Stripe integration instead of extending it, breaking the webhook setup and the session architecture.

Fix: Use version control (git) to see what changed. If you don't have version control... this is going to be hard to untangle.

How to tell if your webhooks are actually working

1. Go to your Stripe dashboard
2. Click Developers → Webhooks
3. Click on your endpoint
4. Look at "Recent deliveries"

You should see green checkmarks for successful deliveries. If you see red X marks or no deliveries at all, that tells you the problem.

If there are no deliveries, Stripe isn't sending webhooks at all — your webhook URL is probably wrong.

If there are red failures, click on one to see the error. The response code tells you what happened:

• 404 — your app doesn't have a page at that address. The webhook URL is wrong.
• 500 — your app received the webhook but crashed trying to process it.
• 401/403 — your app is rejecting the webhook. Usually a signing secret problem.

Why this is dangerous to get wrong

With most bugs, the worst case is "the app doesn't work." With payment bugs, the worst case is you take someone's money and don't deliver what they paid for. That's a refund, a dispute, and potentially a chargeback — which Stripe charges you $15 for, on top of returning the money.

Payment integration is consistently described as "the opposite of vibe coding." It requires exact configuration, correct error handling, and testing with real transactions. The AI gets you 70% of the way there, but the last 30% is where the money (literally) lives.