While I don't work too much in it due to the current lack of time, I built cryptocoinalerts.net (<a href="https://github.com/AlexITC/crypto-coin-alerts" rel="nofollow">https://github.com/AlexITC/crypto-coin-alerts</a>) some months ago, decided to be an open source project from the beginning and while it has served its purpose (put real work in a project that potential clients could evaluate), I ended up extracting a library from it (<a href="https://github.com/AlexITC/playsonify" rel="nofollow">https://github.com/AlexITC/playsonify</a>) which I have being used in other projects.