How to authenticate with GridDB Cloud REST API using API key vs Basic Auth?

I'm trying to query data from GridDB Cloud using its REST/WebAPI endpoint. The official docs mention both Basic Authentication and API key-based access, but I'm unclear on the exact header format and which method is preferred for production use. For Basic Auth,
I've tried the following:

import requests import base64 credentials = base64.b64encode(b"admin:mypassword").decode("utf-8") headers = { "Authorization": f"Basic {credentials}", "Content-Type": "application/json" } url = "https://<cluster-host>/griddb/v2/<cluster-name>/dbs/public/containers" response = requests.get(url, headers=headers) print(response.status_code, response.text)

I consistently receive a 401 Unauthorized response.

Is the cluster hostname format <clusterName>.griddb.net or something else for the GridDB Cloud Free Plan?

Does GridDB Cloud Free Plan support the WebAPI at all, or is it restricted to the GUI and JDBC only?

If API key authentication is available, what is the correct header key name X-API-Key? Authorization: Bearer?

I've already reviewed the GridDB WebAPI documentation and the GridDB Cloud docs, but they don't clearly distinguish between the self-hosted WebAPI and the Cloud-managed endpoint.