Worked on the Shopify/rails repository to enhance backend security by addressing input validation for query string keys. Focused on implementing robust encoding checks to ensure that only properly encoded keys are processed, aligning this validation with existing mechanisms for query values. Utilized Ruby and Ruby on Rails to introduce server-side logic that raises BadRequest errors when invalid-encoded keys are detected, preventing malformed input from reaching business logic and reducing the risk of downstream failures. Added comprehensive end-to-end tests to cover scenarios involving invalid UTF-8 characters in query keys, thereby improving reliability and maintaining compatibility with current request handling processes.