A method of executing an operation across different authentication domains, comprising: receiving, by an initial server system located in an initial authentication domain, a requested operation transmitted in a message from a client system, wherein the requested operation comprises a search operation including at least one search query; in response to determining, by the initial server system, that the requested operation requires at least one resource located in an authentication domain other than the initial authentication domain, creating, by the initial server system in a memory of the initial server system, a redirections list indicating one or more other authentication domains to be contacted by the client system in order to complete the requested operation; transmitting the redirections list from the initial server system to the client system, the redirections list instructing the client system to contact the other authentication domains indicated in the redirections list in order to complete the requested operation; receiving, by the client system, partial results from the other authentication domains, wherein each partial result received from a respective one of the other authentication domains comprises at least one result obtained by applying the requested operation to at least one resource contained in that authentication domain, and wherein each of the received partial results from the other authentication domains comprises a list of documents stored in the other authentication domain that match the search query; aggregating, by the client system in response to the redirections list, the partial results received from the other authentication domains into a single final result, and wherein the client system aggregates the partial results by combining the lists of documents into a final list of documents that match the search query; and displaying, by the client system, the final result to a user of the client system. receiving, by an initial server system located in an initial authentication domain, a requested operation transmitted in a message from a client system, wherein the requested operation comprises a search operation including at least one search query; in response to determining, by the initial server system, that the requested operation requires at least one resource located in an authentication domain other than the initial authentication domain, creating, by the initial server system in a memory of the initial server system, a redirections list indicating one or more other authentication domains to be contacted by the client system in order to complete the requested operation; transmitting the redirections list from the initial server system to the client system, the redirections list instructing the client system to contact the other authentication domains indicated in the redirections list in order to complete the requested operation; receiving, by the client system, partial results from the other authentication domains, wherein each partial result received from a respective one of the other authentication domains comprises at least one result obtained by applying the requested operation to at least one resource contained in that authentication domain, and wherein each of the received partial results from the other authentication domains comprises a list of documents stored in the other authentication domain that match the search query; aggregating, by the client system in response to the redirections list, the partial results received from the other authentication domains into a single final result, and wherein the client system aggregates the partial results by combining the lists of documents into a final list of documents that match the search query; and displaying, by the client system, the final result to a user of the client system.