Guys, you should do your homework before posting...
https://www.robinhood.com/Wikipedia:
Robinhood Markets Inc., or simply Robinhood, is a U.S. based financial services company headquartered in Palo Alto, California. The company offers the Robinhood smartphone mobile app, which allows individuals to invest in publicly traded companies and exchange-traded funds listed on U.S. stock exchanges without paying a commission. The company makes money from interest earned on customers' cash balances and margin lending.
After an April 2017 fundraising, Robinhood had a $1.3 billion valuation.
As of early 2018, Robinhood had 3 million user accounts and this is approximately the same number as the online broker E-Trade.
I am convinced they will succeed. They have a great basement of customers and already are well established when it comes to traditional stock markets. I personally didn't try it yet but am looking forward to observe their development. I am pretty sure it is safe to use from the start.