1. A method for extending an object schema-based application programming interface (API), comprising: receiving, from a user, a schema defining an extension to the API and a reference to a parent node in a graph projection of the API, wherein the graph projection of the API comprises a number of navigable paths, each navigable path representing a function exposed by the API and wherein the extension defines a plurality of functions to be added to the API; verifying that the schema defines a valid extension to the API based at least in part on whether the navigable path comprises a continuous path in the graph projection of the API from a root node of the graph projection of the API to the node representing the extension by determining that a parent node of the extension is an existing node in the graph projection of the API; updating the graph projection of the API to include a node representing the extension and a navigable path to the node representing the extension; and processing a request from the user by traversing through the updated graph projection of the API, the request representing the navigable path to the node representing the extension.