## Authentication schemes 
You can determine whether an API call is client or server-side by the scheme of authentication:
- Client-side — are called without authentication or with the `Authorization` header: `Bearer <user_JWT>` header, where `<user_JWT>` — is the user token.
- Server-side API calls for implementing the user flow — are called with the header: `X-SERVER-AUTHORIZATION: <server_JWT>`, where `<server_JWT>` — is the server token.