API Reference
Send transactional email, manage contacts and audiences, schedule broadcasts, and verify domains over a single REST surface.
Base URL
Every endpoint lives under a single host. Plaintext HTTP is not accepted: connections are terminated with TLS at the edge, so all calls must use https://.
https://api.sevk.io
Payloads are JSON in both directions. Identifiers are opaque strings; do not parse them or assume a length. Timestamps are ISO-8601 in UTC.
Authentication
Attach a project API key to every request as a bearer token. The key determines which project the request acts on and which capabilities are available. There is no per-request project parameter.
Authorization: Bearer YOUR_API_KEY
Response Codes
Standard HTTP semantics apply. 2xx means accepted, not delivered. 4xx means a request or state precondition prevented the operation; follow the error details before retrying. 5xx means a server-side failure. When retrying a send after a timeout or server error, use backoff and reuse the original Idempotency-Key and request body. A failed response does not prove that no email was queued.
| Status | Description |
|---|---|
200 | Successful request. |
201 | Resource created successfully. |
204 | Successful request with no response body. |
400 | Check that the parameters were correct. |
401 | The API key used was missing or invalid. |
403 | The API key does not have permission for this action. |
404 | The resource was not found. |
409 | A resource, idempotency key, or scheduled email state conflicts with the request. |
429 | The rate limit was exceeded. |
500 | Internal server error. |