Base URL and authentication

Base URL

Pick the base URL that matches the format your tool or SDK uses.

For	Base URL	Endpoints used
OpenAI-format SDKs and tools	https://api.vikey.ai/v1	/chat/completions, /responses, /models
Anthropic-format SDKs and tools (including Claude Code)	https://api.vikey.ai	/v1/messages
Token Plan	https://api-plan.vikey.ai/v1	Same as the OpenAI format, model vikey/plan

Mind the /v1

The OpenAI SDK needs the base URL with /v1. The Anthropic SDK and Claude Code need it without /v1, because they add /v1/messages themselves. Getting this wrong is the most common cause of 404 errors.

Sending the API key

Send the key in either header. Both are accepted on every endpoint.

Authorization: Bearer YOUR_API_KEY

x-api-key: YOUR_API_KEY

The OpenAI SDK uses Authorization: Bearer and the Anthropic SDK uses x-api-key. You do not need to set these headers yourself when you use an SDK.

Optional headers

Header	Purpose
X-End-User	An identifier for your own end user (not a Vikey user), such as a customer id in your app. Stored with the usage data. Use 1 to 128 characters: letters, digits, underscore, period, colon or hyphen. Invalid values are ignored, they never fail the request. Do not put emails or phone numbers here.

Checking the balance from the API

The balance is shown in the dashboard. GET /v1/balance only accepts a dashboard login token, not an API key, so in an app rely on the dashboard or handle the 402 error (see Errors).