Authentication
To make direct HTTP requests to the Stream API, you must include your Sitecore Personalize client key as a query string parameter in the URI of the request.
To find your client key, in Sitecore Personalize, on the navigation pane, click 
> Company information > Client key.
Example 32. Sending a client key with a request when retrieving the browser ID
RequestResponse
curl -X GET -g '<baseURL>/v1.2/browser/create.json?client_key=<client_key>'