Alexander developed API Center integration capabilities in the test-repo-billy/azure-rest-api-specs repository, focusing on enabling programmatic management of API sources within Azure API Management. He implemented a new ApiSource resource with full CRUD operations for the Azure API Center resource manager API, allowing users to efficiently manage API sources through standardized interfaces. The work involved updating versioning to include the 2024-06-01-preview release, ensuring compatibility with evolving Azure standards. Alexander utilized TypeSpec for API modeling and leveraged his expertise in API development and Azure Resource Manager to deliver a well-structured, maintainable feature that addressed a specific integration need.