BlogCustomer.io Webhooks

How to Test Customer.io Webhooks

Customer.io reporting webhooks deliver email, push, and SMS engagement events so you can track messaging performance externally.

Customer.io Official Webhook Docs

1. Customer.io Webhook Events

Customer.io can send the following webhook events to your endpoint:

email_delivered
email_opened
email_clicked
email_bounced
email_unsubscribed
push_delivered
sms_delivered

2. Set Up a Test Endpoint with HookRay

Follow these steps to start receiving Customer.io webhooks for testing:

  1. Go to HookRay and click "Start Testing — Free" to get your unique webhook URL.
  2. Copy the URL (e.g., https://h.hookray.com/abc123).
  3. In your Customer.io dashboard, navigate to the webhook settings and paste the HookRay URL as your endpoint.
  4. Select the events you want to receive (see list above).
  5. Trigger a test event — HookRay will show the incoming webhook in real-time.

3. Sample Customer.io Webhook Payload

Here's an example of what a Customer.io webhook payload looks like:

payload.json
{
  "event_id": "01ABC123DEF456",
  "object_type": "email",
  "metric": "delivered",
  "timestamp": 1763595300,
  "data": {
    "customer_id": "cust_42",
    "email_address": "user@example.com",
    "campaign_id": 101,
    "campaign_name": "Welcome Series",
    "subject": "Welcome to HookRay!"
  }
}

4. Common Issues & Troubleshooting

Webhook not arriving?

Check that your endpoint URL is correct and publicly accessible. Customer.io cannot reach localhost URLs — use HookRay's cloud URL instead.

Getting 400 or 500 errors?

HookRay accepts any payload and returns 200 OK by default, so the issue is likely on Customer.io's side. Check your webhook configuration and event selection.

Need to verify webhook signatures?

Customer.io signs webhook requests for security. Use HookRay to capture the raw headers and body, then implement signature verification in your application code.

5. Next Steps

  • Use HookRay's webhook replay feature to re-send captured webhooks while building your handler
  • Enable smart parsing (Pro plan) to see Customer.io-specific fields highlighted automatically
  • Check the Customer.io webhook documentation for the complete event reference

Ready to test Customer.io webhooks?

Get a free webhook URL in 5 seconds. No signup required.

Start Testing Customer.io Webhooks — Free

Test webhooks from other services

StripeGitHubShopifySlackTwilioPayPalSendGridDiscord