When dealing with brokerage houses around the world you need to make sure that you are contracting with a firm licensed by the country's regulators. There are a lot of brokerages that do not hold the correct privileges in order to offer a brokerage service, some countries do not even allow certain products to be transacted within their jurisdiction.
All companies no matter what industry must be registered, but brokerages also need to have regulatory permissions from their local regulators (FCA, SEC, DSFA etc.). If the brokerage does not have the right permissions in place then you or your clients will not be covered and protected against any unlawful activity by the brokerage.
The FCA have highlighted this on their website, as you can see on the following link:
Examples of common misconceptions:
The United States does not allow the use of CFDs
In Switzerland only Banks are allowed to offer CFDs