Worked on the Ecwid/ecwid-java-api-client repository to expand the DiscountBase enum, enabling support for SHIPPING, ITEM, and SUBTOTAL discount applications. This involved updating Kotlin code to introduce new enum values and ensuring they were referenced consistently throughout the API client. Extended test data generation and enhanced the CI/CD workflow using YAML to increase coverage for the new discount bases, reducing the risk of regressions. Focused on improving reliability in discount application logic by addressing gaps in enum presence and usage. The work improved maintainability, reduced runtime error risk, and supported safer, faster rollout of promotional features for the client.