POST
/
api
/
v2
/
emails
import { Inbound } from '@inboundemail/sdk';

const inbound = new Inbound('your_api_key');

const { data, error } = await inbound.email.send({
  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.'
});

if (error) {
  console.error('Error:', error);
} else {
  console.log('Email sent:', data.id);
}

{
  "id": "em_1234567890abcdef",
  "messageId": "0100018e1234abcd-12345678-1234-1234-1234-123456789012-000000"
}
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:
  • 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.
You can use agent@inbnd.dev as a sender without domain verification for testing purposes.
​
to
string | string[]
required
Recipient email address. For multiple addresses, send as an array of strings.
Combined total of all recipients (to, cc, bcc) should not exceed 50 addresses.
​
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.
Also accepts replyTo (camelCase) for Resend compatibility.
​
replyTo
string | string[]
Reply-to email address (Resend-compatible camelCase format). 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.
​
tags
array
Array of tag objects for email categorization and tracking (Resend-compatible).
​
attachments
array
Array of file attachments (max 40MB total email size, 25MB per attachment, 20 attachments max).

​
Headers

​
Authorization
string
required
Bearer token for API authentication.
​
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

import { Inbound } from '@inboundemail/sdk';

const inbound = new Inbound('your_api_key');

const { data, error } = await inbound.email.send({
  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.'
});

if (error) {
  console.error('Error:', error);
} else {
  console.log('Email sent:', data.id);
}

​
Response

​
id
string
required
Unique identifier for the sent email in Inbound’s system
​
messageId
string
AWS SES Message ID for tracking the email through AWS infrastructure.
Not included in idempotent responses (when using Idempotency-Key header for duplicate requests).
{
  "id": "em_1234567890abcdef",
  "messageId": "0100018e1234abcd-12345678-1234-1234-1234-123456789012-000000"
}

​
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
Supported Resend Features:
  • All basic email parameters (from, to, subject, html, text, etc.)
  • Both reply_to (snake_case) and replyTo (camelCase) formats
  • Both content_type and contentType for attachments
  • tags array for email categorization
  • content_id for CID embedding in attachments
  • Remote file fetching via path parameter in attachments
Unsupported Resend Features:
  • scheduled_at parameter (use /api/v2/emails/schedule endpoint instead)
  • React components (use HTML/text instead)
  • Some advanced attachment features may differ
1.0 - ✅