curl -X PATCH 'https://api.resend.com/emails/email-id' \
  -H "Authorization: Bearer $RESEND_API_KEY" \
  -H 'User-Agent: my-app/1.0'

# PATCH /emails/{email_id} (Resend API)
Base URL: https://api.resend.com
Auth: Authorization: Bearer <RESEND_API_KEY>
Last verified: 2026-09-03

> Update a single email

## 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 PATCH 'https://api.resend.com/emails/email-id' \
  -H "Authorization: Bearer $RESEND_API_KEY" \
  -H 'User-Agent: my-app/1.0'

## Parameters
| Name | In | Type | Required | Description |
| :--- | :--- | :--- | :--- | :--- |
| email_id | path | string | Yes | The ID of the email. |

## Response (200 OK)
{"scheduled_at":"string"}

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

PATCH

/emails/{email_id}

Resend API

Update a single email

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
→ 162 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 PATCH 'https://api.resend.com/emails/email-id' \  -H "Authorization: Bearer $RESEND_API_KEY" \  -H 'User-Agent: my-app/1.0'

Get a free Resend API key → sponsored

Parameters

Name	In	Type	Required	Description
email_id	path	string	Yes	The ID of the email.

Response 200 OK

{
  "scheduled_at": "string"
}