Worked on the kiesraad/abacus repository to enhance the reliability and maintainability of election data processing. Focused on backend development using Rust, the developer implemented a context-aware method for calculating the exact number of eligible voters, ensuring accurate election counting and improved data integrity. Additionally, they refactored the validation layer to return structured ValidationResults, replacing mutable state and streamlining error handling across multiple modules. These changes not only improved the clarity and robustness of the validation process but also contributed to more maintainable code. The work demonstrated strong skills in Rust, backend architecture, and data validation within a critical application domain.