Transactional API | Owlat Docs

Send published transactional templates to a recipient.

Endpoint

Method	Path
`POST`	`/api/v1/transactional`

Request body

Provide either transactionalId or slug.

{
  "slug": "order-confirmation",
  "email": "john@example.com",
  "dataVariables": {
    "firstName": "John",
    "orderNumber": "ORD-12345"
  },
  "language": "en",
  "addToAudience": true,
  "attachments": [
    {
      "filename": "invoice.pdf",
      "url": "https://example.com/invoices/12345.pdf",
      "contentType": "application/pdf"
    }
  ]
}

Fields:

transactionalId or slug (required, one of these)
email (required)
dataVariables (optional object)
language (optional language code, e.g. en, de, en-US)
addToAudience (optional boolean)
attachments (optional array) — file attachments to include with the email

Attachments

Each attachment object has the following fields:

Field	Type	Required	Description
`filename`	string	Yes	The file name shown to the recipient
`content`	string	One of `content` or `url`	Base64-encoded file content
`url`	string	One of `content` or `url`	URL to fetch the file from
`contentType`	string	No	MIME type (e.g., `application/pdf`, `image/png`)

Limits:

Maximum 10 attachments per email
Maximum 10 MB total attachment size

Response

Accepted sends return queued status:

{
  "data": {
    "status": "queued",
    "email": "john@example.com",
    "transactionalEmailId": "j57...",
    "slug": "order-confirmation",
    "contactId": "j58...",
    "contactCreated": true,
    "language": "en"
  }
}

Language resolution order

Explicit language in request
Contact preferred language (if recipient exists)
Template default language
Fallback default

Validation and delivery checks

Template must exist and be published
Template must have rendered HTML content
Sending domain must be verified
dataVariables are validated against template schema when present