During May 2025, Mirko enhanced the Backbase/openapi-tools repository by improving Mustache template encoding for complex API parameter types. He focused on expanding JSON encoding support within Mustache templates to handle container parameters and free-form objects, addressing edge cases that previously caused reliability issues in generated API clients and servers. Mirko updated the _param.mustache template to align encoding logic, ensuring consistency across template rendering. His work demonstrated proficiency in Mustache templating, JSON encoding, and template rendering, resulting in more robust and maintainable API tooling. The depth of these changes improved developer experience and reduced the likelihood of encoding-related failures.