5 Webhook Debugging Mistakes That Cost You Hours

After helping thousands of developers debug webhooks, we've seen the same mistakes over and over. These aren't bugs in your code — they're process mistakes that turn a 10-minute fix into a 3-hour ordeal.

Here are the five most common webhook debugging mistakes and how to avoid them.

Mistake #1: Re-triggering Webhooks Instead of Replaying

The mistake: Every time you need to test your webhook handler, you go back to Stripe's dashboard (or Shopify, or GitHub) and trigger a new test event. Change one line of code? Trigger another event. Add a log statement? Trigger another event.

Why it costs you hours: Each trigger takes 30-60 seconds. Do that 50 times while debugging, and you've lost 25-50 minutes just waiting. Plus, each test event has slightly different data (new IDs, timestamps), making it harder to compare behavior.

Mistake #2: Not Logging the Raw Payload

The mistake: You parse the webhook payload immediately and only log processed data. When something goes wrong, you can't see what was actually received.

// Bad: Only logging processed data
app.post('/webhook', (req, res) => {
  const event = JSON.parse(req.body);
  console.log('Event type:', event.type); // Not enough!
  // ...
});

Why it costs you hours: When a webhook fails, you need to see exactly what was sent. Was a field missing? Was it in an unexpected format? Without the raw payload, you're guessing.

// Good: Log raw payload first
app.post('/webhook', (req, res) => {
  console.log('Raw webhook:', JSON.stringify(req.body));
  console.log('Headers:', JSON.stringify(req.headers));
  
  const event = JSON.parse(req.body);
  // ...
});

Mistake #3: Not Handling Duplicate Webhooks

The mistake: Assuming each webhook will only be delivered once. Your code processes the same payment twice, creating duplicate orders or double-charging customers.

Why it costs you hours: This bug often doesn't show up in testing because you're only triggering webhooks manually. In production, webhook providers retry failed deliveries, and network issues can cause duplicates. Debugging production data corruption is painful.

// Good: Check for duplicates
app.post('/webhook', async (req, res) => {
  const event = JSON.parse(req.body);
  
  // Check if already processed
  const existing = await db.webhookEvents.findOne({ eventId: event.id });
  if (existing) {
    console.log('Duplicate webhook, skipping:', event.id);
    return res.status(200).send('OK');
  }
  
  // Store event ID before processing
  await db.webhookEvents.insert({ eventId: event.id, receivedAt: new Date() });
  
  // Now process the event
  // ...
});

Mistake #4: Not Testing Edge Cases

The mistake: Only testing the happy path. Your webhook handler works great for payment_intent.succeeded, but crashes on payment_intent.payment_failed or when a field is unexpectedly null.

Why it costs you hours: Edge cases show up in production at the worst times. A customer's payment fails, your webhook handler crashes, and now you're debugging at 2 AM.

Common edge cases to test:

• Null or missing optional fields
• Empty arrays vs. arrays with many items
• Zero amounts, negative amounts
• Unicode characters in strings
• Very long strings
• Unexpected event types

Mistake #5: Debugging Without Breakpoints

The mistake: Relying entirely on console.log statements to debug webhooks. Add a log, trigger the webhook, check the output, add another log, trigger again...

Why it costs you hours: Each iteration takes time. With breakpoints, you can inspect every variable at once, step through the code, and understand exactly what's happening.

The traditional problem with breakpoint debugging on webhooks is that the webhook provider times out while you're stepping through code. With replay-based debugging, this isn't an issue — you're in complete control.

Bonus: The Ultimate Webhook Debugging Checklist

Before you start debugging, make sure you have:

• Raw payload logging enabled
• The exact payload that caused the issue (captured or from logs)
• A way to replay the webhook without re-triggering
• Breakpoints set in your IDE
• Test cases for edge cases ready
• Idempotency handling in place

Summary

Most webhook debugging pain comes from process problems, not code problems. The five mistakes we covered:

1. Re-triggering instead of replaying — Capture once, replay infinitely
2. Not logging raw payloads — Always log before processing
3. Not handling duplicates — Implement idempotency
4. Not testing edge cases — Edit payloads to simulate failures
5. Debugging without breakpoints — Use replay to control timing

Fix these process issues and you'll spend less time debugging and more time building.