We all know the good feeling that comes from starting a green field project and being able to use all the great new technology. But what if you have a 460k LOC monolith but you really feel that a new GraqhQL API is the way to go. Well, if you have good design, you can totally do it, and here's how. GraphQL is all the rage for good reason. It's geared towards solving the problems REST API's have when used by modern front-end apps. However, new technology often has a way of breaking apart when subjected to legacy projects. How easy is it to create a GraphQL API for a commercial project with 7 years of active development and 400k users? What difficulties might you encounter that blurbs and blog posts won't tell you about? I'll cover all that and more in this riveting tale of fun, sweat and tears (of joy).