How to Test Notion Webhooks

This guide covers everything you need to test Notion webhooks — how to inspect the raw payload, verify the signature, forward events to localhost, and reproduce any delivery in your local development environment without needing a real Notion event.

How to Test Notion Webhooks with WebhookWhisper

1. Create a free endpoint — click Create Live Endpoint above to get a permanent public HTTPS URL (no account required to try)
2. Register the URL in Notion — paste the WebhookWhisper URL into Notion's webhook settings
3. Trigger a test event — use the one-click test payload sender or trigger a real event in Notion
4. Inspect the request — see the full headers, raw body, and Notion signature header in real time
5. Forward to localhost — add a forwarding rule to relay the event to your local handler (e.g. http://localhost:3000/webhooks/notion)

Notion Webhook Signature Verification

Notion signs webhook deliveries using HMAC-SHA256. The signature is sent in the X-Notion-Signature header. Always verify this signature before processing the payload to ensure the request came from Notion and was not tampered with in transit.

Node.js Verification

const crypto = require('crypto')
const express = require('express')
const app = express()

app.post('/webhooks/notion',
  express.raw({ type: 'application/json' }),
  (req, res) => {
    const secret = process.env.NOTION_WEBHOOK_SECRET
    const signature = req.headers['x-notion-signature']

    // Compute expected HMAC — always use raw body, never parsed JSON
    const expected = crypto
      .createHmac('sha256', secret)
      .update(req.body)
      .digest('hex')

    if (!crypto.timingSafeEqual(Buffer.from(signature || ''), Buffer.from(expected))) {
      return res.status(401).json({ error: 'Invalid signature' })
    }

    const event = JSON.parse(req.body)
    // Process event here — respond first, process async for slow operations
    res.json({ received: true })
  }
)

Python (FastAPI) Verification

import hashlib, hmac, os
from fastapi import FastAPI, Request, HTTPException

app = FastAPI()

@app.post('/webhooks/notion')
async def webhook(request: Request):
    secret = os.environ['NOTION_WEBHOOK_SECRET'].encode()
    raw_body = await request.body()
    signature = request.headers.get('x-notion-signature', '')

    expected = hmac.new(secret, raw_body, hashlib.sha256).hexdigest()

    if not hmac.compare_digest(signature, expected):
        raise HTTPException(status_code=401, detail='Invalid signature')

    payload = await request.json()
    return {'received': True}

Common Notion Webhook Errors

Forward Notion Webhooks to Localhost

Use WebhookWhisper to receive Notion webhook events at a public HTTPS URL and relay them to your local development server — no tunnel, no CLI install, no public server required.

1. Create a WebhookWhisper endpoint and paste it into Notion's webhook settings
2. In the Forwarding tab, set target URL to http://localhost:3000/webhooks/notion
3. Every Notion event appears in the inspector and hits your local handler simultaneously
4. Use event replay (Pro) to re-send any captured event without triggering a new action in Notion

FAQ

Do I need a Notion account to test webhooks?

No. WebhookWhisper includes a one-click Notion sample payload so you can fire a realistic test event and verify your handler without a Notion account or triggering a real Notion action.

How do I find my Notion webhook secret?

The webhook signing secret is shown in Notion's developer settings or webhook configuration page. Each webhook endpoint gets its own secret — do not share secrets between endpoints.

What is the Notion webhook timeout?

Most providers timeout after 5–30 seconds. If your handler does slow operations (database writes, external API calls), respond with HTTP 200 immediately and process the event in a background job to avoid triggering Notion's retry logic.