Supported endpoints

The API accepts three request formats on one host. Each model works only in the formats that this table shows. We make the table from our model catalogue each time that you open this page.

A request for a model on an endpoint that does not serve it gets a 400 error before we charge money. The error message names the endpoint to use:

{
  "error": {
    "message": "Model \"claude-sonnet-5-5\" is not served on /v1/responses. Use /v1/messages or /v1/chat/completions.",
    "type": "invalid_request_error",
    "param": "model",
    "code": "unsupported_endpoint",
    "details": { "served_on": ["/v1/messages", "/v1/chat/completions"] }
  }
}

Base URL

Client	Base URL
OpenAI SDKs, OpenCode, Codex	https://api.kontinentai.com/v1
Anthropic SDKs, Claude Code	https://api.kontinentai.com

The OpenAI clients add /chat/completions or /responses to the base URL. The Anthropic clients add /v1/messages.

Key headers

Each endpoint that costs money accepts the key in one of two headers:

Authorization: Bearer sk-kont-...
x-api-key: sk-kont-...

The OpenAI SDKs send the first header. The Anthropic SDKs send the second header. Claude Code sends the first header with ANTHROPIC_AUTH_TOKEN and the second header with ANTHROPIC_API_KEY. GET /v1/models needs no key. See Authentication.

Request bodies

• /v1/chat/completions reads the body and makes a new request from it. It accepts only the parameters on Chat completions. It refuses a different parameter with a 400 error that names the parameter.
• /v1/messages and /v1/responses send your body to the model as you wrote it. We change only model. On the starter balance, we also lower max_tokens or max_output_tokens to 4,096. The model makes the decision about the other fields.

/v1/messages needs model, max_tokens and messages. /v1/messages also sends your anthropic-version and anthropic-beta headers to the model.

Errors

The error format agrees with the format of the endpoint, so that the error classes of each SDK work.

/v1/chat/completions, /v1/responses and /v1/models use the OpenAI format:

{
  "error": {
    "message": "Insufficient balance: $0.001230 required, $0.000400 available",
    "type": "insufficient_quota",
    "param": null,
    "code": "INSUFFICIENT_BALANCE"
  }
}

/v1/messages and /v1/messages/count_tokens use the Anthropic format:

{
  "type": "error",
  "error": {
    "type": "billing_error",
    "message": "Insufficient balance: $0.001230 required, $0.000400 available"
  },
  "request_id": "req_8f2a1c"
}

The HTTP status is the same in the two formats. For the list of statuses, see Errors.

Idempotency

Send an Idempotency-Key header to make a retry safe. The rules are the same on /v1/chat/completions, /v1/messages and /v1/responses:

• The header works only on a request without stream: true.
• A request with the header and stream: true gets a 400 error with the code idempotency_unsupported_for_stream.
• A repeat of a completed request gets the first response again, with the header Idempotent-Replay: true. We do not charge for the repeat.

See Idempotency.

The cost block

A response without stream: true has a kontinent block. The block is at the top level of the JSON, so the SDKs ignore it:

"kontinent": {
  "request_id": "req_8f2a1c",
  "cost_micros": 13,
  "cost_usd": 0.000013,
  "list_price_usd": 0.000061,
  "saved_usd": 0.000048
}

Field	What it is
request_id	The id of the request. The x-request-id header has the same value
cost_micros	The cost of the request in micro-dollars. One micro-dollar is $0.000001. This is the amount that we take from your balance
cost_usd	The same cost in US dollars
list_price_usd	The cost of the same tokens at the official price of the maker
saved_usd	list_price_usd minus cost_usd