Developed a foundational feature for the Shopify/rails repository, introducing a default transaction isolation level to ActiveRecord transactions. This work established the with_default_isolation_level mechanism, which was integrated into the transaction flow to enable safer and more controlled database interactions. By focusing on Ruby and Ruby on Rails, the implementation provided a smoother migration path to newer isolation levels, reducing deployment risk and improving data consistency during database migrations. The approach demonstrated expertise in back end development, database transaction management, and incremental migration strategies, setting the groundwork for gradual adoption of stronger isolation levels across services without disrupting existing workflows.