Send Emails API

Send emails directly through Mailpulse with automatic open and click tracking. Emails are sent via your verified sending domain using the Resend infrastructure.

Sending Domain

You have two options for the sender address:

Custom domain (recommended) — Add and verify your own domain in Settings > Sending Domains for full branding control.
Platform domain (fallback) — If your from domain is not verified, Mailpulse automatically rewrites the sender to @send.mailpulse-io.lyten.agency and sets reply-to to your original address so recipients can still reply to you.

For example, if you send from Newsletter <news@example.com> without verifying example.com, the email will be sent from Newsletter <news@send.mailpulse-io.lyten.agency> with reply-to: news@example.com.

Send Email

Endpoint


POST /api/send

Request Body

Field	Type	Required	Description
`from`	`string`	Yes	Sender address (e.g. `Your Name <you@yourdomain.com>`)
`to`	`string \| string[]`	Yes	Recipient email address(es)
`subject`	`string`	Yes	Email subject line
`htmlContent`	`string`	Yes	HTML content of the email
`replyTo`	`string`	No	Reply-to email address
`cc`	`string \| string[]`	No	CC recipient(s)
`bcc`	`string \| string[]`	No	BCC recipient(s)
`campaignId`	`string`	No	Campaign name to associate with
`metadata`	`object`	No	Custom metadata to store

Example Request


curl -X POST NEXT_PUBLIC_BASE_URL/api/send \
  -H "x-api-key: your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "Newsletter <news@yourdomain.com>",
    "to": "recipient@example.com",
    "subject": "Welcome to our newsletter",
    "htmlContent": "<html><body><h1>Hello!</h1><a href=\"https://example.com\">Visit us</a></body></html>",
    "campaignId": "welcome-series",
    "metadata": { "userId": "123" }
  }'

Response Schema

Field	Type	Description
`id`	`string`	Resend email ID
`emailTrackingId`	`string`	Mailpulse tracking ID
`from`	`string`	Sender address used
`to`	`string[]`	Recipient addresses
`subject`	`string`	Email subject
`links`	`TrackedLink[]`	Tracked links with original and tracking URLs
`pixelUrl`	`string`	Open tracking pixel URL

Example Response


{
  "id": "re_abc123",
  "emailTrackingId": "hE4kJ9xP",
  "from": "Newsletter <news@yourdomain.com>",
  "to": ["recipient@example.com"],
  "subject": "Welcome to our newsletter",
  "links": [
    {
      "originalUrl": "https://example.com",
      "trackingId": "mN2pQ7",
      "trackingUrl": "https://mailpulse-io.lyten.agency/api/t/c/mN2pQ7"
    }
  ],
  "pixelUrl": "https://mailpulse-io.lyten.agency/api/t/o/hE4kJ9xP"
}

How It Works

When you call POST /api/send, Mailpulse:

Checks if the sender domain is verified — if not, falls back to the platform domain
Extracts all links from the HTML content
Creates tracking records for the email and each link
Rewrites all links to pass through Mailpulse tracking endpoints
Injects a 1x1 tracking pixel for open detection
Sends the modified HTML via Resend
Triggers the EMAIL_SENT webhook if configured

All opens and clicks are then tracked automatically — no additional setup needed.

Difference with Register Email

	`POST /api/send`	`POST /api/emails`
Sends the email	Yes (via Resend)	No (returns modified HTML)
Requires sending domain	No (falls back to platform domain)	No
Tracking	Automatic	You inject pixel/links yourself
Use case	Send + track in one call	Track emails sent by another service

Use /api/send when you want Mailpulse to handle both sending and tracking. Use /api/emails when you send emails through your own provider (Gmail, SendGrid, SMTP, etc.) and only need tracking.

Error Responses

Status	Description
`400 Bad Request`	Missing required fields or invalid JSON
`401 Unauthorized`	Invalid or missing API key
`500 Internal Server Error`	Email delivery failed