This Finpip overview summarizes FXOpen as commonly marketed to retail traders (founded 2005; HQ: London, United Kingdom). Typical platforms include MetaTrader 4, MetaTrader 5, TickTrader.
Regulatory snapshot (not legal advice): FCA; ASIC; FSC Mauritius
Official website: https://www.fxopen.com/. Confirm licence numbers, product availability, and costs there before funding an account.