Transactional Send API
Send transactional emails immediately or schedule them for later delivery using predefined message templates.
Authentication
This endpoint requires both project and message scoping:
prj_api_key(query parameter) — Required to scope the request to a project:POST /api/v1/send?prj_api_key=YOUR_PROJECT_KEY.msg_api_key(JSON body parameter) — Required in the request payload to identify which message template to use:{ "msg_api_key": "msg_xxx" }.
If both are provided, SendPromptly validates the message belongs to the given project and returns a 404 if it does not.
Endpoint summary
| Method | Endpoint | Description |
|---|---|---|
| POST | /api/v1/send | Send transactional email |
Each endpoint follows this structure: Parameters, Example Request, Responses, Errors.
Send Transactional Email
POST /api/v1/send
Send an email using a predefined message template. The email can be sent immediately or scheduled for later delivery.
Query Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
prj_api_key | string | Yes | Project API key |
Request Body
| Parameter | Type | Required | Description |
|---|---|---|---|
msg_api_key | string | Yes | Message API key (identifies which email template to use) |
email | string | No* | Recipient email address (*required for email messages) |
first_name | string | No | Recipient first name |
last_name | string | No | Recipient last name |
template_variables | object | No | Variables to substitute in email template |
schedule_message | boolean | No | Whether to send immediately (false) or queue (true, default) |
delay_hours | integer | No | Hours to delay sending (0-720) |