curl -X POST 'https://api.resend.com/segments' \
  -H "Authorization: Bearer $RESEND_API_KEY" \
  -H 'User-Agent: my-app/1.0' \
  -H 'Content-Type: application/json' \
  -d '{
  "name": "string",
  "audience_id": "string",
  "filter": {}
}'

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

> Create a new segment

## 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/segments' \
  -H "Authorization: Bearer $RESEND_API_KEY" \
  -H 'User-Agent: my-app/1.0' \
  -H 'Content-Type: application/json' \
  -d '{"name":"string","audience_id":"string","filter":{}}'

## Parameters
| Name | In | Type | Required | Description |
| :--- | :--- | :--- | :--- | :--- |
| name | body | string | Yes | The name of the segment. |
| audience_id | body | string | No | The ID of the audience this segment belongs to. |
| filter | body | object | No | Filter conditions for the segment. |

## Response (200 OK)
{"id":"78261eea-8f8b-4381-83c6-79fa7120f1cf","object":"segment"}

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

POST

/segments

Resend API

Create a new segment

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
→ 215 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/segments' \  -H "Authorization: Bearer $RESEND_API_KEY" \  -H 'User-Agent: my-app/1.0' \  -H 'Content-Type: application/json' \  -d '{  "name": "string",  "audience_id": "string",  "filter": {}}'

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Parameters

Name	In	Type	Required	Description
name	body	string	Yes	The name of the segment.
audience_id	body	string	No	The ID of the audience this segment belongs to.
filter	body	object	No	Filter conditions for the segment.

Response 200 OK

{
  "id": "78261eea-8f8b-4381-83c6-79fa7120f1cf",
  "object": "segment"
}