POST
/
api
/
v2
/
emails
curl -X POST 'https://inbound.new/api/v2/emails' \
     -H 'Authorization: Bearer your_api_key' \
     -H 'Content-Type: application/json' \
     -d '{
  "from": "Acme <noreply@yourdomain.com>",
  "to": ["customer@example.com"],
  "subject": "Welcome to Acme!",
  "html": "<h1>Welcome!</h1><p>Thanks for signing up.</p>",
  "text": "Welcome! Thanks for signing up."
}'

{
  "id": "em_1234567890abcdef"
}
This endpoint is compatible with Resend’s email sending API, making it easy to migrate from Resend to Inbound.

​
Authentication

This endpoint requires authentication via either:
  • Session-based auth: Valid session cookie from login
  • API key auth: Bearer token in Authorization header

​
Body Parameters

​
from
string
required
Sender email address.To include a friendly name, use the format "Your Name <sender@domain.com>".
You must own and have verified the sender’s domain in your Inbound account.
​
to
string | string[]
required
Recipient email address. For multiple addresses, send as an array of strings. Max 50.
​
subject
string
required
Email subject.
​
bcc
string | string[]
Bcc recipient email address. For multiple addresses, send as an array of strings.
​
cc
string | string[]
Cc recipient email address. For multiple addresses, send as an array of strings.
​
reply_to
string | string[]
Reply-to email address. For multiple addresses, send as an array of strings.
​
html
string
The HTML version of the message.
​
text
string
The plain text version of the message.
​
headers
object
Custom headers to add to the email.
​
attachments
array
Filename and content of attachments (max 40MB per email, after Base64 encoding).

​
Headers

​
Authorization
string
Bearer token for API authentication. Required if not using session auth.
​
Idempotency-Key
string
Add an idempotency key to prevent duplicated emails.
  • Should be unique per API request
  • Idempotency keys expire after 24 hours
  • Have a maximum length of 256 characters

​
Request Example

curl -X POST 'https://inbound.new/api/v2/emails' \
     -H 'Authorization: Bearer your_api_key' \
     -H 'Content-Type: application/json' \
     -d '{
  "from": "Acme <noreply@yourdomain.com>",
  "to": ["customer@example.com"],
  "subject": "Welcome to Acme!",
  "html": "<h1>Welcome!</h1><p>Thanks for signing up.</p>",
  "text": "Welcome! Thanks for signing up."
}'

​
Response

{
  "id": "em_1234567890abcdef"
}

​
Important Notes

Domain Verification Required: You can only send emails from domains that you own and have verified in your Inbound account. Attempting to send from an unverified domain will result in a 403 error.
Email Limits: Your account has a monthly email sending limit based on your subscription plan. The API will return a 429 error if you exceed this limit.
Idempotency: Use the Idempotency-Key header to ensure emails aren’t sent multiple times in case of network issues or retries.

​
Migration from Resend

This endpoint is designed to be compatible with Resend’s email sending API. To migrate:
  1. Replace your Resend API endpoint with https://inbound.new/api/v2/emails
  2. Replace your Resend API key with your Inbound API key
  3. Ensure your sending domain is verified in Inbound
The following Resend features are not yet supported:
  • scheduled_at parameter for scheduling emails
  • tags array for email tagging
  • React components (use HTML/text instead)