coinpayments
CoinPayments is a cloud wallet solution that offers an easy way to integrate a checkout system for numerous cryptocurrencies. Coinpayments now also offers coin conversion via Shapeshift.io.
zcore-lib
A pure and powerful JavaScript Bitcoin library.
cryptocurrency-cli
Cryptocurrency CLI lets you monitor cryptocurrencies in your portfolio and track your earnings through the command line. It uses the coinmarketcap.com API to fetch crypto data.