Open and Click Tracking

• Using the dashboard
• Using the API

Go to the Domains page and click on the domain you want to configure.In the Configuration tab, click Configure under Enable tracking metrics.Provide a name for your tracking subdomain, enable open and/or click tracking, and click +Add domain.Add the CNAME record to your DNS settings (e.g. Cloudflare, GoDaddy, etc.) to verify your tracking subdomain.

If we detect CAA records on your domain, we will show an additional CAA record that needs to be created. This ensures that we can issue a TLS certificate for your tracking subdomain.

Click I’ve added the records to verify the domain.Once verified, all tracked links in your emails will use your custom tracking subdomain.

You can add a tracking subdomain when creating a new domain by passing the tracking_subdomain field along with click_tracking and/or open_tracking.

Node.js

PHP

Python

Ruby

Go

Rust

Java

.NET

cURL

import { Resend } from 'resend';

const resend = new Resend('re_xxxxxxxxx');

const { data, error } = await resend.domains.create({
  name: 'example.com',
  openTracking: true,
  clickTracking: true,
  trackingSubdomain: 'links',
});

If you already have a domain, you can call the update endpoint to add a tracking subdomain and enable tracking.

Node.js

PHP

Python

Ruby

Go

Rust

Java

.NET

cURL

import { Resend } from 'resend';

const resend = new Resend('re_xxxxxxxxx');

const { data, error } = await resend.domains.update({
  id: 'd91cd9bd-1176-453e-8fc1-35364d380206',
  openTracking: true,
  clickTracking: true,
  trackingSubdomain: 'links',
});

Whether creating or updating a domain, the API will return the required DNS records that need to be added to your domain provider’s DNS settings. Note the Tracking record.

API Response Example

{
  "id": "4dd369bc-aa82-4ff3-97de-514ae3000ee0",
  "name": "example.com",
  "created_at": "2026-03-28T17:12:02.059593+00:00",
  "status": "not_started",
  "open_tracking": true,
  "click_tracking": true,
  "tracking_subdomain": "links",
  "capabilities": {
    "sending": "enabled",
    "receiving": "disabled"
  },
  "records": [
    // ... other records ...
    {
      "record": "Tracking",
      "name": "links.example.com",
      "type": "CNAME",
      "value": "links1.resend-dns.com",
      "ttl": "Auto",
      "status": "not_started"
    }
  ],
  "region": "us-east-1"
}

Add the required CNAME record to your domain provider’s DNS settings (e.g. Cloudflare, GoDaddy, etc.).

If we detect CAA records on your domain, we will show an additional CAA record that needs to be created. This ensures that we can issue a TLS certificate for your tracking subdomain.

Once you’ve added the required DNS record(s), call the verify endpoint to verify the domain.

Node.js

PHP

Python

Ruby

Go

Rust

Java

.NET

cURL

import { Resend } from 'resend';

const resend = new Resend('re_xxxxxxxxx');

const { data, error } = await resend.domains.verify(
  'd91cd9bd-1176-453e-8fc1-35364d380206',
);

Tracking is active only when both of these conditions are met:

1. The open_tracking or click_tracking setting is enabled for the domain.
2. A tracking subdomain is configured (e.g., links.example.com) and successfully verified.

All tracked links in your emails will use your tracking subdomain.View the API reference for more details.

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How Open Tracking Works

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How Click Tracking Works

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Troubleshooting

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Occasional Extra Verification Step

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Changing the Tracking Subdomain

• Not removable: After your tracking subdomain has been created, it can only be changed, never removed. This behavior preserves any email links that may already be sent with the current tracking subdomain. For this reason, do not remove old tracking DNS records. (All previously used records remain active and are included in the response.)
• Requires verification: After changing the tracking subdomain, a new DNS record must be verified. Until then, the previous value is used.
• Update time limitations: Changes are limited to once every 24 hours.

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Removing a Domain with a Tracking Subdomain