@Hantje: As of today, OctaFX broker does not have regulation in Indonesia.
@Hantje: So if it's not regulated in Indonesia, does that mean it's illegal?
Yes, it's illegal in Indonesia, but legal in its country. None of the brokers from abroad have regulations in Indonesia. All of these brokers have regulations in their country of origin.
So, does the lack of regulation in Indonesia automatically mean it's not good? No. Brokers like Interactive Brokers, Saxo Bank, Oanda have been operating for more than 20 years and have stricter regulations such as CFTC, FCA UK, FSA (Japan).
How can it have so many traders from Indonesia? How does that work? They also have a website that uses Indonesian.
Brokers that have regulations in their country of origin are allowed to accept clients from other countries. Broker OctaFX has regulation in the country of Cyprus under the regulator CySEC with license number 372/18. This broker can accept clients from countries outside of Cyprus, including Indonesia.