Methods and systems for secure client-side communication between multiple domains is provided. Such methods and systems can provide for decreased communication latency particularly effective for dynamic multi-domain and/or multi-tenant environments while allowing for granular security or specific security of messages and operations with regard to users, user sessions, groups, organizations, permissions sets, applications, or any other logical delineation. Such methods and systems may involve a variety of security components, for example, at least one set of instructions including a plurality of defined instruction to be utilized by users of the set of instructions to communicate, and cryptographic construct data in order to verify the data integrity and the authenticity of messages sent and received using the secure client-side communication between multiple domains.