Klaviyo Webhook Testing — Debug Klaviyo Events Instantly

To test Klaviyo webhooks, you need a public HTTPS endpoint that Klaviyo can POST to. WebhookWhisper gives you one instantly — no CLI, no deployment, no ngrok required. Paste the URL into your Klaviyo dashboard, trigger a test event, and inspect the full payload in real time.

Why Test Klaviyo Webhooks with WebhookWhisper?

Klaviyo webhooks deliver real-time notifications for profile, metric, and list events from your email and SMS marketing flows.

WebhookWhisper captures every incoming Klaviyo event with full headers, body, and timing data — so you can debug integration issues without deploying to a public server.

Klaviyo Webhook Events

The following events are commonly sent by Klaviyo:

• profile.created
• profile.updated
• metric.created
• list.member.added

How to Test Klaviyo Webhooks Locally

1. Create your endpoint — Sign up free and get a permanent HTTPS URL in seconds.
2. Add the URL to Klaviyo — Paste your WebhookWhisper URL into your Klaviyo webhook settings.
3. Enable forwarding (optional) — Add a forwarding rule to relay events to localhost:3000 or any local port.
4. Trigger a test event — Use Klaviyo's dashboard or the one-click test sender to fire a profile.created event.
5. Inspect in real time — See the full payload, headers, and response in your WebhookWhisper dashboard.

Klaviyo Webhook Signature Verification

Klaviyo signs every webhook request using the X-Klaviyo-Signature header. Always verify this signature in production to prevent spoofed requests.

// Node.js — Verify Klaviyo webhook signature
const crypto = require('crypto');

function verifyKlaviyoSignature(payload, signature, secret) {
  const expected = crypto
    .createHmac('sha256', secret)
    .update(payload)
    .digest('hex');
  return crypto.timingSafeEqual(
    Buffer.from(expected),
    Buffer.from(signature)
  );
}

Common Klaviyo Webhook Errors

• 401 Unauthorized — Signature mismatch. Check that you are using the raw request body (not parsed JSON) for HMAC verification.
• Webhook not received — Verify the URL is publicly accessible. WebhookWhisper endpoints are always public — no tunneling needed.
• Timeout errors — Klaviyo expects a 2xx response within a few seconds. Respond immediately and process the event asynchronously.
• Duplicate events — Klaviyo retries webhook delivery 3 times with increasing delay on failure. Always use the event ID for idempotency checks.

Frequently Asked Questions

How do I test Klaviyo webhooks for free?

Sign up for a free WebhookWhisper account and get a permanent HTTPS endpoint. Add it to your Klaviyo webhook settings and trigger a test event from the Klaviyo dashboard.

Can I test Klaviyo webhooks without deploying?

Yes. WebhookWhisper gives you a public HTTPS URL that requires no deployment. Use the built-in forwarding rules to relay events to your local development server.

How do I receive Klaviyo webhooks on localhost?

Create a forwarding rule in WebhookWhisper pointing to your local port (e.g. http://localhost:3000/webhook). Every incoming event is relayed to your local server with retry logic.

What is the Klaviyo webhook retry policy?

Klaviyo retries webhook delivery 3 times with increasing delay on failure.