headfon.es is a ground-up implementation of the Spotify web player. The main features are search, albums, playlists and a custom theme selector. Under the hood it leverages the Spotify API for library data and the Web Playback SDK for playback.

On the server side is a Node.JS server running express with mongoDB. API fetches are wrapped in a GraphQL server, mapping the server data to client components using TypeScript for development. I wrote a medium article discussing how I implemented authentication.