We recently launched our sentiment and opinions APIs for top 200 cryptocurrencies. Here is the link: https://cryptoqokka.com/developer
More info - see slides: https://cryptoqokka.com/slides
We were hoping that this is something that could really help people get a quantitative view of where the market is going, and where the opportunities are. Over the last two months we tested the APIs with some algorithmic traders and app developers (wallet, asset management, portfolio, etc.), and we would love to explore more use cases. Please let us know if you have any feedback or suggestions.