I am looking for Relative Strenght Index and other market indicators API's for cryptos. I don't think TradingView provides one but maybe you know one?
I had the same problem, couldn’t seem to find a good API that supported most of the popular indicators, and at the same time covered all the exchanges. So I decided to start up a project for this. So check out https://taapi.io . We cover 200+ indicators, pattern recognitions etc… I’m a big fan of free products myself, so taapi.io is free as well.
If your indicator isn’t there, then shoot us message, and we’ll get it added!
You can calculate it yourself. Use an API to get the gains and losses over an period of 14 points and put it into the formula described here: http://stockcharts.com/school/doku.php?id=chart_school:technical_indicators:relative_strength_index_rsi
The https://iexcloud.io/ API delivers a powerful toolset with dozens of indicators available. They now support a variety of cryptocurrencies as well. The most cost-effective platform I have seen yet.