This is the server used by both Trends with Friends (https://play.google.com/store/apps/details?id=com.dachsteam.trendswithfriends) and Trends Kotlin (the Kotlin version of the app).
It uses Node and the google-trends-api (https://www.npmjs.com/package/google-trends-api) to send the necessary Google Trends data to the app. The data expected and returned is encoded JSON.