API reference · Authentication

One key, both protocols.

Every request is authenticated with a key that starts with sdn_. How you present it depends on which protocol you are speaking.

Getting a key

Keys are created and revoked in the dashboard under /dashboard/keys. A key is shown once at creation — store it somewhere safe. Keys are always prefixed sdn_.

Note

Treat keys as secrets. Set them through environment variables rather than committing them, and rotate from the dashboard if one leaks.

How to present the key

Protocol	Endpoint	Header
Anthropic Messages	`/v1/messages`	`x-api-key: sdn_...`
OpenAI Chat Completions	`/v1/chat/completions`	`Authorization: Bearer sdn_...`
OpenAI Responses	`/v1/responses`	`Authorization: Bearer sdn_...`
Embeddings / Completions / Batches	`/v1/...`	`Authorization: Bearer sdn_...`

The Anthropic endpoint also accepts Authorization: Bearer sdn_... as an alternative to x-api-key, which is convenient when a client only lets you set one auth header.

Examples

curl https://api.sideren.io/v1/messages \
  -H "x-api-key: sdn_your_key" \
  -H "content-type: application/json" \
  -d '{"model":"sdn-gpt-oss-120b","max_tokens":256,"messages":[{"role":"user","content":"Hi"}]}'

Anthropic — x-api-key

curl https://api.sideren.io/v1/chat/completions \
  -H "authorization: Bearer sdn_your_key" \
  -H "content-type: application/json" \
  -d '{"model":"sdn-gpt-oss-120b","messages":[{"role":"user","content":"Hi"}]}'

OpenAI — Authorization: Bearer

Failure modes

A missing or malformed key returns 401 with an error body shaped for the protocol you called.
A valid key naming a model that does not exist in the catalog returns 404 — check the id against GET /v1/models.

See Errors for the full status-code reference and body shapes.