Our OpenAPI supports 3 of the standard OAuth Authorization protocols, all of which require manual action in the authentication flow.
To minimize manual input, we can recommend manually logging in once, and keeping the session alive by periodically requesting refresh tokens.
Authentication without manual steps is available only for our institutional partners with Certificate Based Authentication (CBA). This authentication method is available for server-to-server integrations, and requires no manual input to authenticate users. Due to regulatory requirements, CBA unfortunately cannot be made available to retail or corporate clients.
GitHub - Examples on retrieving and refreshing the authentication token
Learn page - OAuth Certificate Based Authentication