Interactive Brokers LLC is a member of NYSE, FINRA, SIPC. Interactive Brokers Group (IB Group) and its predecessor companies have been building trading technology for 40 years with a mission to provide liquidity on better terms.
IB offers broad number of instruments to trade. From Stocks, and FX Spot, Futures, to Options and many more.
Personally I trade FX, and Currency Futures Options with them.
-1 star for their platform. TWS is beast with steep learning curve. It took me couple of weeks to get into it. But on the other hand, it's obvious because it allows to trade variety of different instruments.