Send Transactional Email

Send a transactional email to one or more recipients.

Use Cases:

• Order confirmation emails
• Password reset emails
• Account verification emails
• Payment receipts
• Shipping notifications
• Welcome emails
• Any one-off automated email

Content Modes:
You can send emails in two ways:

1. Raw HTML Mode: Provide html (required) and optionally text content directly
2. Template Mode: Reference a published template by its uniqueSlug identifier

These modes are mutually exclusive - provide either template or html, not both.

Template-Based Sending:

{
  "from": "noreply@yourdomain.com",
  "to": "customer@example.com",
  "template": {
    "id": "order_confirmation",
    "variables": {
      "firstName": "John",
      "orderNumber": "12345",
      "total": 99.99
    }
  }
}

When using templates:

• The template must be published (have a publishedVersionId)
• Variables are substituted using {{variableName}} syntax
• Missing variables are replaced with empty strings
• Subject and previewText can be overridden by providing them in the request
• The text field cannot be used with templates (it comes from the template)

Behavior:

• Email is queued and sent asynchronously
• Returns immediately with the email send ID
• Delivery status is tracked via webhooks
• Supports HTML and plain text content
• Plain text is auto-generated from HTML if not provided
• Supports attachments (up to 25 files, 25MB total)
• Custom metadata can be attached for tracking

Required Scope: smtp:send

Rate Limits:

• 100 emails per minute per API key
• Maximum 10MB HTML content
• Maximum 25 attachments (total 25MB)

Delivery Tracking:

• Use the returned email ID to track delivery status
• Configure webhooks to receive delivery notifications
• Events: delivered, bounced, complained, opened, clicked

Best Practices:

• Always include a plain text version for accessibility
• Keep HTML under 100KB for best deliverability
• Use verified sending domains only
• Include unsubscribe links for marketing content