This server is intended to be run locally while using the Response Area Sandbox. It acts as a proxy between the Sandbox (running within a web browser) and an evaluation function.

Web browsers send a preflight request before every GET or POST request which uses the OPTIONS verb. Evaluation functions (running locally or on AWS) are not configured to respond to OPTIONS requests, so this proxy is responsible for replying to the preflight request and forwarding just the POST request to the evaluation function.