Webhook Debugger, Logger & API Mocker

Wed, 31 Dec 2025 21:56:44 +0000

I just shipped Webhook Debugger v2.7 – an open-source tool that generates temporary webhook URLs and logs every incoming request in real-time. No localhost tunneling, no complex setup, no ngrok required.

If you've ever spent hours debugging why your Stripe payment webhook isn't working, this post is for you.

What Problem Does This Solve?

Imagine this scenario: You're building an e-commerce checkout flow. Stripe sends a payment_intent.succeeded webhook to your server, but your order confirmation email never sends.

The traditional debugging workflow:

Add console.log statements everywhere
Deploy to staging
Make a test purchase
Check server logs (nothing useful)
Realize Stripe couldn't reach localhost
Set up ngrok tunnel
Update webhook URL in Stripe dashboard
Repeat test purchase
Still nothing...

This takes hours. With Webhook Debugger, it takes 30 seconds.

How It Works

Step 1: Start the Actor (one click on Apify)

Step 2: Get your webhook URLs instantly:

https://<run-id>.runs.apify.net/webhook/wh_abc123
https://<run-id>.runs.apify.net/webhook/wh_def456
https://<run-id>.runs.apify.net/webhook/wh_ghi789

Step 3: Configure Stripe/GitHub/Shopify to send webhooks to these URLs

Step 4: See every request in real-time:

{
  "id": "evt_8m2L5p9xR",
  "timestamp": "2025-12-28T12:00:00Z",
  "webhookId": "wh_abc123",
  "method": "POST",
  "headers": {
    "content-type": "application/json",
    "stripe-signature": "t=123456789,v1=abc..."
  },
  "body": {
    "type": "payment_intent.succeeded",
    "data": { "amount": 9999 }
  },
  "statusCode": 200,
  "processingTime": 8
}

Now you can see exactly what Stripe is sending – the headers, the payload, everything.

Key Features for Developers

Real-Time Streaming

Monitor webhooks as they arrive using Server-Sent Events:

curl -N https://<actor-url>/log-stream

Every new webhook appears instantly in your terminal.

API Mocking

Simulate different response codes to test your error handling:

# Simulate a 500 error
curl https://<actor-url>/webhook/wh_abc123?__status=500

# Simulate a 401 Unauthorized
curl https://<actor-url>/webhook/wh_abc123?__status=401

Request Replay

Captured a webhook but need to test it against your local server? Replay it:

curl "https://<actor-url>/replay/wh_abc123/evt_xyz?url=http://localhost:3000/webhook" \
  -H "Authorization: Bearer YOUR_KEY"

The original request is forwarded to your local endpoint with all original headers intact.

Custom Response Bodies

Mock any API response:

{
  "defaultResponseCode": 201,
  "defaultResponseBody": "{\"status\": \"created\", \"orderId\": \"ord_12345\"}"
}

Perfect for testing how your system handles specific API responses.

Enterprise Security Features

For production debugging, security matters:

Feature	Description
API Key Auth	Require Bearer tokens for all requests
IP Whitelisting	Lock endpoints to specific IPs/CIDRs
Rate Limiting	Per-IP throttling on management endpoints
Data Masking	Auto-redact Authorization headers from logs

Example secure configuration:

{
  "authKey": "my-secret-key-2025",
  "allowedIps": ["54.240.0.0/16"],
  "maskSensitiveData": true,
  "rateLimitPerMinute": 30
}

What's New in v2.7?

The latest release adds hot-reloading – you can now update your configuration without restarting:

Change your authKey → applies immediately
Add more webhook URLs → generates instantly
Update custom scripts → recompiles in real-time

This is critical during live debugging sessions where restarting would lose your captured data.

Real-World Use Cases

Stripe Payment Debugging

{
  "forwardUrl": "http://localhost:3000/stripe-webhook",
  "jsonSchema": {
    "type": "object",
    "required": ["type", "data"],
    "properties": {
      "type": { "type": "string" }
    }
  }
}

Validates Stripe payloads and forwards them to your local server simultaneously.

GitHub Actions Recovery

Missed a critical deployment webhook? Replay it:

# Find the missed event
curl "https://<actor-url>/logs?method=POST&limit=10" \
  -H "Authorization: Bearer YOUR_KEY"

# Replay to your CI system
curl "https://<actor-url>/replay/wh_abc123/evt_missed?url=https://ci.internal/deploy"

Shopify Flow Testing

Use custom scripts to transform webhooks before logging:

// Parse nested JSON and add debug flags
if (event.contentType === "application/json") {
  const body = JSON.parse(event.body);
  event.body = {
    ...body,
    _debugMode: true,
    _receivedAt: Date.now(),
  };
}

Getting Started in 60 Seconds

Go to Webhook Debugger on Apify
Click Start
Copy your webhook URLs from the output
Configure your service to send to those URLs
Watch requests arrive in the Dataset tab

That's it. No installation, no configuration files, no tunnels.

FAQ

Q: How long are URLs valid?
A: Default is 24 hours, configurable up to 72 hours.

Q: Is my data stored?
A: Only in your personal Apify dataset. You own it, it's automatically deleted after retention expires.

Q: What's the payload limit?
A: 10MB default, configurable up to 100MB.

Q: Can I use this with Zapier?
A: Yes! Use the forwarding feature to pipe webhooks to your Zap's catch URL.

Conclusion

Webhook Debugger solves a real problem that every developer faces: debugging invisible HTTP requests. Instead of guessing what went wrong, you get complete visibility into every request.

The key features that make this tool production-ready are:

Real-time SSE streaming for instant visibility
Request replay for testing and recovery
Enterprise security with auth, IP whitelisting, and rate limiting
Hot-reloading for zero-downtime configuration
Custom scripting for payload transformation

The project is open-source on GitHub, and you can try it immediately on the Apify Store.

Stop debugging blindly. Start seeing your webhooks.

Questions or feature requests? Open an issue on GitHub or reach out in the Apify Discord.

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