curl -X POST 'https://api.resend.com/domains' \
  -H "Authorization: Bearer $RESEND_API_KEY" \
  -H 'User-Agent: my-app/1.0' \
  -H 'Content-Type: application/json' \
  -d '{
  "name": "string",
  "region": "us-east-1",
  "custom_return_path": "string",
  "open_tracking": true,
  "click_tracking": true,
  "tls": "opportunistic",
  "capabilities": {
    "sending": "enabled",
    "receiving": "enabled"
  },
  "tracking_subdomain": "string"
}'

# POST /domains (Resend API)
Base URL: https://api.resend.com
Auth: Authorization: Bearer <RESEND_API_KEY>
Last verified: 2026-09-03

> Create a new domain

## Critical Gotchas
* All requests must include a `User-Agent` header (e.g. `User-Agent: my-app/1.0`) or the API returns HTTP 403.
* The `to` field is an array of strings, even when sending to a single recipient.

## cURL
curl -X POST 'https://api.resend.com/domains' \
  -H "Authorization: Bearer $RESEND_API_KEY" \
  -H 'User-Agent: my-app/1.0' \
  -H 'Content-Type: application/json' \
  -d '{"name":"string","region":"us-east-1"}'

## Parameters
| Name | In | Type | Required | Description |
| :--- | :--- | :--- | :--- | :--- |
| name | body | string | Yes | The name of the domain you want to cr... |
| region | body | string | No | The region where emails will be sent... |
| custom_return_path | body | string | No | For advanced use cases, choose a subd... |

## Response (200 OK)
{"id":"string","name":"string"}

---
Need an API key? Get one at https://resend.com/signup

POST

/domains

Resend API

Create a new domain

Base URL: https://api.resend.com
Auth: Authorization: Bearer <RESEND_API_KEY>
Last verified: 2026-09-03 · upstream hash matched

Actions

Agents: curl -H "Accept: text/markdown" this URL
→ 220 tokens · Vary: Accept

Critical gotchas

All requests must include a User-Agent header (e.g. User-Agent: my-app/1.0) or the API returns HTTP 403.

The to field is an array of strings, even when sending to a single recipient.

cURL

curl -X POST 'https://api.resend.com/domains' \  -H "Authorization: Bearer $RESEND_API_KEY" \  -H 'User-Agent: my-app/1.0' \  -H 'Content-Type: application/json' \  -d '{  "name": "string",  "region": "us-east-1",  "custom_return_path": "string",  "open_tracking": true,  "click_tracking": true,  "tls": "opportunistic",  "capabilities": {    "sending": "enabled",    "receiving": "enabled"  },  "tracking_subdomain": "string"}'

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Parameters

Name	In	Type	Required	Description
name	body	string	Yes	The name of the domain you want to create.
region	body	string	No	The region where emails will be sent from. Possible values are us-east-1 \| eu-west-1 \| sa-east-1 \| ap-northeast-1
custom_return_path	body	string	No	For advanced use cases, choose a subdomain for the Return-Path address. Defaults to 'send' (i.e., send.yourdomain.tld).
open_tracking	body	boolean	No	Track the open rate of each email.
click_tracking	body	boolean	No	Track clicks within the body of each HTML email.
tls	body	string	No	TLS mode. Opportunistic attempts secure connection but falls back to unencrypted. Enforced requires TLS or email won't be sent.
capabilities	body	object	No	Configure the domain capabilities for sending and receiving emails. At least one capability must be enabled.
tracking_subdomain	body	string	No	The subdomain to use for click and open tracking.

Response 200 OK

{
  "id": "string",
  "name": "string",
  "created_at": "2023-10-06 23:47:56.678+00",
  "status": "pending",
  "capabilities": {
    "sending": "enabled",
    "receiving": "enabled"
  },
  "records": [
    {
      "record": "SPF",
      "name": "string",
      "type": "MX",
      "ttl": "string",
      "status": "pending",
      "value": "string",
      "priority": 0
    }
  ],
  "region": "string",
  "open_tracking": true,
  "click_tracking": true,
  "tracking_subdomain": "string"
}