{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"$id": "https://raw.githubusercontent.com/api-evangelist/nylas/main/json-schema/nylas-transactional-send-message-schema.json",
"title": "transactional_send_message",
"x-generated": "2026-10-02",
"x-method": "derived",
"x-generator": "derive-json-schema.py",
"x-source": "openapi/nylas-transactional-send-api-openapi.yml#/components/schemas/transactional_send_message",
"type": "object",
"properties": {
"id": {
"type": "string",
"description": "The message ID."
},
"attachments": {
"type": "array",
"description": "An array of Attachment objects. For google, linked Google Drive files are not included. For Microsoft, linked One Drive files are not included.",
"items": {
"$ref": "#/$defs/attachment_transactional_send"
},
"uniqueItems": true,
"minItems": 0
},
"bcc": {
"type": "array",
"description": "An array of name/email address pairs that the message was BCC'd to. For received messages, this\nis nearly always empty.",
"items": {
"$ref": "#/$defs/message-participant"
}
},
"body": {
"type": "string",
"description": "The body of the message. This field is the same as the `body` field in your request."
},
"cc": {
"type": "array",
"description": "An array of name/email address pairs that the message was CC'd to.",
"items": {
"$ref": "#/$defs/message-participant"
}
},
"from": {
"type": "array",
"description": "A list of name/email address pairs that the message was sent from. For transactional send, this will always be one pair.",
"items": {
"$ref": "#/$defs/message-participant-response"
},
"uniqueItems": true
},
"object": {
"type": "string",
"description": "The object type of the response (in this case, `message`)."
},
"reply_to": {
"type": "array",
"items": {
"$ref": "#/$defs/message-participant"
},
"uniqueItems": true,
"description": "An array of name/email address pairs that should receive replies to the message."
},
"snippet": {
"type": "string",
"minLength": 1,
"description": "A short snippet (the first 100 characters, with HTML tags removed) of the message body. This is\nuseful for displaying a preview of the message."
},
"subject": {
"type": "string",
"description": "The subject of the message."
},
"tracking_options": {
"type": "object",
"description": "Tracking options for the message.",
"properties": {
"opens": {
"type": "boolean",
"description": "When `true`, shows that message open tracking is enabled."
},
"links": {
"type": "boolean",
"description": "When `true`, shows that link clicked tracking is enabled."
},
"label": {
"type": "string",
"description": "A label describing the message tracking purpose.",
"maxLength": 2048
}
}
},
"to": {
"type": "array",
"description": "An array of name/email address pairs that the message was sent to.",
"items": {
"$ref": "#/$defs/message-participant"
},
"uniqueItems": true
}
},
"$defs": {
"attachment_transactional_send": {
"description": "A file attachment for a transactional email message.",
"type": "object",
"properties": {
"content_type": {
"type": "string",
"minLength": 1,
"description": "The [MIME type](https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types) of the attachment, used by the email client to determine how to display the attachment. If you don't provide a type, Nylas infers it from the file name.\nThe value of this field is exactly the same as the email attachment's `Content-Type` header.\nThe provider might set additional parameters, such as `name` and `charset`.\n\nNylas returns an empty `content_type` field if an attachment file name contains non-ASCII characters (for example, accented characters like `ΓΌ`). This is because Google can't detect its content type."
},
"filename": {
"type": "string",
"minLength": 1,
"description": "The file name of the attachment."
},
"content_id": {
"type": "string",
"description": "(Inline attachments only) The alphanumeric `cid` from the `
` tag in the message's HTML. For\nexample, you might see something like `
` in\nthe message body.\n\nSometimes, the `content_id` value is contained in angle brackets (for example,\n``)."
},
"content_disposition": {
"type": "string",
"description": "(Not supported for Microsoft and EWS) The content disposition of the attachment. Usually, this is `inline` or `attachment` followed by the file name (for example, `inline; filename=\"some-image.jpeg\"`)."
},
"is_inline": {
"type": "boolean",
"description": "If `true`, indicates that the attachment is an inline file."
},
"size": {
"type": "integer",
"description": "The size of the attachment, in bytes."
}
}
},
"message-participant": {
"title": "Message participant",
"type": "object",
"description": "A name/email address pair.",
"properties": {
"name": {
"type": "string"
},
"email": {
"type": "string",
"format": "email"
}
},
"required": [
"email"
]
},
"message-participant-response": {
"title": "Message participant response",
"type": "object",
"description": "A name/email address pair.",
"properties": {
"name": {
"type": "string"
},
"email": {
"type": "string",
"format": "email"
}
}
}
}
}