I built my own audio player too.
https://github.com/nzoschke/jukelab
It's a web app with the Spotify Web Playback SDK or a good old MP3 HTTP server and API like Internet Archive.
It works crazy well on a ChromeBook, and reasonably well on an iPhone, iPad or Android both through a native app with a webview component or the browser.
I have a theory the pendulum is swinging back and there is a demand for controlling our own music and music interface, and web technology is sufficiently good for implementing players.
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