Lazy Builders and Eager Compiles: Taming Type Graphs in Public APIs

This retrospective on reviving a legacy C# package demonstrates key API design patterns essential when scaling from internal code to public libraries. The author's lazy builder pattern defers validation to aggregate errors and prevent breaking changes; type stubs declare surfaces before implementation is ready. These practices—combined with automated API surface management—offer a roadmap for the costly decision of committing to public APIs.