Balrog is the software that runs the server side component of the update system used by Firefox and other Mozilla products. It helps ship updates faster and with much more flexibility than it's predecessor AUS (Application Update Service). However, Balrog's Admin API is mostly hand-written code, with some usage of wtforms for validation. It largely works, but it has some rough spots and inconsistencies. The move to an OpenAPI Specification will have multiple benefits including less code maintenance, multiple UI and backend bug fixes, better documentation and easier for clients to visualize and interact with API’s resources. Connexion, a framework designed for flask-based applications, will be used to handle HTTP requests based on OpenAPI Specification of the API to map the endpoints to the Balrog’s existing methods for serving the requests.