A bearer token and an API key both prove an app has permission to call an API but are not the same: an API key is a static credential (32-64 characters) tied to your account, while a bearer token is a delivery format for any credential placed in the Authorization: Bearer header. Sportmonks issues an API key sent as a bearer token, avoiding OAuth flows, refresh tokens, and token expiry, and the article warns against using the ?api_token= query parameter in production.