Configure a custom Return Path

By default, Resend uses the send subdomain for the Return-Path address.

Domains that show CNAME records for sending use your Return-Path subdomain for one record and an r-prefixed sibling for the other. With a Return-Path of outbound, you’ll be shown records for both outbound.example.com and routbound.example.com, and both need to be added for the domain to fully verify.

You can provide a custom Return-Path address when you add a new domain in the Dashboard under Advanced options, or by setting the optional custom_return_path parameter when creating a domain via the API or with the domains create CLI command.

The Return-Path is set when the domain is created and cannot be changed afterwards, so custom_return_path is not accepted by the Update Domain endpoint. To use a different Return-Path subdomain, delete the domain and add it again with the new value.

For the API, optionally pass the custom return path parameter.

import { Resend } from 'resend';

const resend = new Resend('re_xxxxxxxxx');

resend.domains.create({ name: 'example.com', customReturnPath: 'outbound' });

$resend = Resend::client('re_xxxxxxxxx');

$resend->domains->create([
  'name' => 'example.com',
  'custom_return_path' => 'outbound'
]);

import resend

resend.api_key = "re_xxxxxxxxx"

params: resend.Domains.CreateParams = {
  "name": "example.com",
  "custom_return_path": "outbound"
}

resend.Domains.create(params)

require "resend"

Resend.api_key = "re_xxxxxxxxx"

params = {
  name: "example.com",
  custom_return_path: "outbound"
}
domain = Resend::Domains.create(params)
puts domain

package main

import "github.com/resend/resend-go/v4"

func main() {
	client := resend.NewClient("re_xxxxxxxxx")

	params := &resend.CreateDomainRequest{
		Name:             "example.com",
		CustomReturnPath: "outbound",
	}

	client.Domains.Create(params)
}

use resend_rs::{types::CreateDomainOptions, Resend, Result};

#[tokio::main]
async fn main() -> Result<()> {
  let resend = Resend::new("re_xxxxxxxxx");

  let _domain = resend
    .domains
    .create(CreateDomainOptions::new("example.com").with_custom_return_path("outbound"))
    .await?;

  Ok(())
}

import com.resend.*;
import com.resend.core.exception.ResendException;
import com.resend.services.domains.model.CreateDomainOptions;
import com.resend.services.domains.model.CreateDomainResponse;

public class Main {
    public static void main(String[] args) throws ResendException {
        Resend resend = new Resend("re_xxxxxxxxx");

        CreateDomainOptions params = CreateDomainOptions
                .builder()
                .name("example.com")
                .customReturnPath("outbound")
                .build();

        CreateDomainResponse domain = resend.domains().create(params);
    }
}

using Resend;

IResend resend = ResendClient.Create( "re_xxxxxxxxx" ); // Or from DI

var resp = await resend.DomainAddAsync( new DomainAddData {
   DomainName = "example.com",
   CustomReturnPath = "outbound"
} );
Console.WriteLine( "Domain Id={0}", resp.Content.Id );

curl -X POST 'https://api.resend.com/domains' \
     -H 'Authorization: Bearer re_xxxxxxxxx' \
     -H 'Content-Type: application/json' \
     -d $'{
  "name": "example.com",
  "custom_return_path": "outbound"
}'

Custom return paths must adhere to the following rules:

Must be 63 characters or less.
Must start with a letter, and end with a letter or number.
Must contain only letters, numbers, and hyphens.

Avoid setting values that could undermine credibility (e.g. testing), as they may be exposed to recipients in some email clients.

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Configure a custom Return Path