Roel de Vries worked on the Amsterdam/amsterdam-schema repository, focusing on schema definition and data validation using JSON. During the month, he addressed a data type mismatch for the duur field across the natuurlijkePersonen and nietNatuurlijkePersonen schemas. By aligning both schemas to the correct duration type, Roel improved validation reliability and reduced the risk of data drift and downstream errors. His work supported ongoing schema hardening and data quality initiatives, with changes tracked through a descriptive commit. The depth of his contribution lay in ensuring consistent data standards, which is essential for robust schema management and long-term maintainability.