x-api-key is accepted as an alternative for clients that cannot set an Authorization header.
Environments
A key is valid in one environment only. Using a sandbox key against production returns
api_key_invalid.
Keeping keys safe
- Call the API from your server. Public clients get scoped tokens, never a secret key.
- Store keys in your secret manager or environment, never in source control.
- The built-in request runner accepts sandbox keys for inspection and does not persist them. Do not reproduce that pattern in a public client.
- Revoke an exposed key and create its replacement in the Developer Platform.
- Use HTTPS. If a key is sent over plain HTTP, treat it as compromised and replace it.

