I built a webhook testing API in one day and listed it on RapidAPI for free

#javascript #software #node #api

The Problem

Every developer integrating M-Pesa, Stripe, GitHub, or any service
that sends webhooks hits the same wall during development:

You need a URL to receive the webhook. But your app is running on
localhost. So you either:

Deploy just to test (slow)
Use ngrok (another tool to manage)
Hard-code a URL and hope for the best

I got tired of this on every project. So I built an API that solves
it in one call.

What I Built

WebhookBox — an API that gives you instant, disposable webhook
URLs for capturing, inspecting, and replaying HTTP payloads.

// Step 1: Create a webhook URL
const response = await fetch(
  'https://webhookbox-api-production.up.railway.app/webhooks/create',
  { method: 'POST' }
)
const { webhook_url, webhook_id } = await response.json()

// Step 2: Point M-Pesa/Stripe/GitHub at webhook_url
// Step 3: Inspect what was received
const payloads = await fetch(
  `https://webhookbox-api-production.up.railway.app/webhooks/${webhook_id}/payloads`
)

That's it. No setup. No config. No ngrok.

What It Does

Create a disposable webhook URL instantly
Capture any HTTP method — POST, GET, PUT, PATCH
Inspect full payload: headers, body, query params, timestamp
Replay any captured payload to a target URL
Auto-expires after 24 hours

The Stack

Node.js + Express
Upstash Redis (for payload storage with TTL)
Deployed on Railway (free tier)
Listed on RapidAPI

Why This Is Useful in CI/CD

The real power is automating webhook testing in your pipeline:

// In your test file
const { webhook_id, webhook_url } = await createWebhook()

// Trigger your payment flow
await triggerMpesaPayment({ callback_url: webhook_url })

// Wait, then assert
await sleep(3000)
const { payloads } = await getPayloads(webhook_id)
assert(payloads[0].body.ResultCode === 0)