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Transactional

Send transactional email

Queues a transactional email for sending. You can either:

  • Provide a slug to use a saved template
  • Provide subject and body to send custom content directly

Recipients:

  • to can be a single email or an array of up to 50 emails
  • Duplicate emails are automatically deduplicated

Attachments:

  • Attachments can be provided as Base64-encoded content or URLs
  • Maximum total attachment size: 40MB per email
  • Any file type supported (PDFs, images, documents, etc.)

A successful response means the email was accepted for background processing. If a recipient is suppressed because of a bounce, complaint, or unsubscribe, the worker records the send as suppressed instead of delivering it.

Optionally set from (domain must be verified) and replyTo addresses. Variables can be passed to customize the email content. Nested objects and arrays are supported for repeat blocks, such as items. Returns immediately with a job ID.

post/transactional/send

Request body

slugstring

Slug of the transactional email template to use (mutually exclusive with subject/body)

subscriberExternalIdstring

Customer-owned subscriber ID for attaching analytics and localization on single-recipient sends. Only valid when sending to exactly one recipient.

subjectstring

Email subject (required if not using slug)

bodystring

Email body HTML content (required if not using slug)

previewstring

Preview text for the email (only used with direct content)

variablesobject

Variables for template replacement (works with both modes). Values can be scalars, nested objects, or arrays used by repeat blocks. Raw HTML templates can use simple subscriber/custom-attribute conditionals such as {{#if subscriber.plan}}...{{else}}...{{/if}} and {{#unless subscriber.plan}}...{{/unless}}.

fromstring

Custom from address. Format: "Name <email>" or just "email". The domain must be verified for your account. If not verified, this field is silently ignored.

replyTostring

Reply-to address. Format: "Name <email>" or just "email". Can be any valid email address.

Example request

{
  "slug": "welcome-email",
  "subscriberExternalId": "user_123",
  "subject": "Welcome to our platform!",
  "body": "<h1>Welcome!</h1><p>Thanks for signing up.</p>",
  "preview": "Welcome to our platform",
  "variables": {
    "NAME": "John",
    "event": {
      "items": [
        {
          "title": "Pro plan",
          "description": "Monthly subscription"
        }
      ]
    }
  },
  "from": "Notifications <notifications@example.com>",
  "replyTo": "Support <support@example.com>",
  "attachments": [
    {
      "filename": "invoice.pdf",
      "path": "https://example.com/invoices/123.pdf"
    }
  ]
}

Response

Email queued successfully

OR

Example response

{
  "success": true,
  "jobId": "job_abc123"
}

Changes