Keizai is an open-source, Postman-inspired tool designed to revolutionize Soroban smart contract testing. It features an intelligent user interface that auto-loads contract information, provides real-time event listening, and offers helpful documentation. The tool streamlines the testing workflow with features for setting up collections, initiating contract invocations, and running test scripts. It also supports seamless team collaboration with easy import/export of collections and various authentication options.