Worked on the fastapi/fastapi repository to enhance the stability of API responses involving Decimal values by addressing edge cases related to NaN and Infinity. Using Python and leveraging backend development and testing skills, updated the decimal_encoder to handle these special cases, preventing TypeError exceptions during JSON encoding. This fix improved API reliability for clients consuming responses with Decimal data and reduced the risk of production incidents. Added comprehensive regression tests to ensure long-term stability and prevent future regressions in the encoding path. The work demonstrated a focus on software quality and robust handling of complex data serialization scenarios in API development.