We've implemented a new serverless continuous integration (CI) architecture that significantly reduces test execution time while preserving the isolation of each test, without incurring additional costs. Our approach involves using multiple AWS profiles to create isolated environments instantly, and leveraging parallelism across these accounts to reduce deployment duration. We've also updated our CI tool, "the Uber deploy", to support multiple profile names, fast-failure detection, and retries, as well as improved handling of concurrent executions on limited resources. By running integration and E2E tests concurrently across a number of isolated accounts, we can significantly improve the efficiency of our deployment process while maintaining the robustness of our CI/CD pipeline.