API Reference

SDKs

The SDK wraps every endpoint below with typed methods (emails.send, emails.get, batch.send, batch.get) and returns { data, error } instead of throwing on API errors. Each endpoint page shows the SDK call alongside the raw HTTP request. Other languages can call the HTTP API directly.

Base URL

All endpoints are versioned under /v1.

Authentication

Every request must include your API key as a Bearer token:

Authorization: Bearer rt_xxxxxxxxxxxxxxxx

Keys are created in the dashboard and shown once. A missing, malformed, or revoked key returns 401 unauthorized:

{
  "error": {
    "code": "unauthorized",
    "message": "Provide your API key as `Authorization: Bearer rt_...`"
  }
}

Response format

Responses are JSON. Errors always have the shape:

{
  "error": {
    "code": "some_error_code",
    "message": "Human-readable explanation"
  }
}

See Errors for the full list of codes.

Endpoints

Asynchronous sending

Submitting an email returns 202 Accepted immediately with status queued. A worker drains the queue at the platform’s provider rate, retries transient failures with exponential backoff, and dead-letters an email as failed only after all retries are exhausted. Track outcomes by polling Get Email / Get Batch, or push-based via Webhooks.