Daniil Redin expanded the discount application logic in the Ecwid/ecwid-java-api-client repository by introducing new bases—SHIPPING, ITEM, and SUBTOTAL—through enhancements to the DiscountBase enum. He ensured these new options were fully integrated across the API client’s code paths, addressing gaps that could lead to runtime errors. Using Kotlin and YAML, Daniil extended test data generation and updated the CI workflow to increase coverage for the new discount bases, reducing regression risk. His work focused on maintainability and traceability, with clear commit messages and issue linkage, ultimately enabling safer and faster rollout of promotional features for the business.