Fortsend API

Quickstart

1. Sign in to the dashboard and add your sender domain.
2. Create the DNS records shown for the domain at your DNS provider, then click “Check DNS”.
3. Create a mailbox (for example noreply@yourdomain.com) once the domain is provisioned.
4. Create an API key and store the secret — it is shown exactly once.
5. Send email with one POST request.

curl -X POST https://fortsend.com/api/send \
  -H "Authorization: Bearer fs_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "noreply@yourdomain.com",
    "to": "customer@example.com",
    "subject": "Your receipt",
    "text": "Thanks for your order.",
    "html": "<p>Thanks for your order.</p>"
  }'

A successful call returns HTTP 202:

{
  "data": {
    "id": "msg_…",
    "from": "noreply@yourdomain.com",
    "to": "customer@example.com",
    "subject": "Your receipt",
    "status": "sent",
    "messageId": "…",
    "createdAt": "2026-06-10T12:00:00.000Z"
  }
}

Authentication

The send endpoint authenticates with a bearer API key: Authorization: Bearer fs_…. Keys carry the email:send scope only — they can never manage domains, mailboxes, or other keys. Management endpoints authenticate with your dashboard session (Clerk). Secrets are stored as SHA-256 hashes; a lost key cannot be recovered, only revoked and replaced.

Endpoints

Domain verification records

Adding a domain returns these records. Ownership and MX must resolve before the domain is provisioned.

Limits

• Send rate: 120 requests per minute per workspace by default. Exceeding it returns 429 with a Retry-After header.
• Monthly quota: enforced per workspace against your plan. Quota exhaustion returns 429.
• Payload: subject up to 998 characters; text and HTML bodies up to 500,000 characters each.

Errors