Worked on backend improvements for zio/zio-aws and zio/zio-http, focusing on API design and schema validation using Scala. Addressed a timing issue in zio/zio-aws by refining the call duration aspect to prevent repeated processing and ensure accurate duration metrics, reducing potential side effects for consumers. Enhanced zio/zio-http’s OpenAPI generation by introducing username validation with regex patterns and enforcing non-empty sequence constraints in generated schemas. Added targeted tests to verify that non-empty payload requirements are correctly reflected. The work emphasized robust schema generation and validation, leveraging skills in Aspect-Oriented Programming, OpenAPI Specification, and comprehensive backend testing practices.