Techniques are provided for augmenting the capabilities of the standard OAuth2 authorization framework in such a way as to allow clients to consume the services of multiple resource servers residing in disjoint security domains while requiring only a single one-time user authentication. An access token that provides access to resource services distributed across a plurality of security domains is partitioned into a plurality of reduced-scope access tokens. Each reduced-scope access token is limited to a subset of authorization scopes of the access token, providing access to a resource service in a particular security domain based upon the subset.