I believe that a license may not always be required to run a crypto gambling business. The necessity of a license depends on the regulations in the jurisdictions (potentially more than one) where: your business is registered, where the servers are located, and where the players connect to your service from. By carefully considering all of these conditions, you will be able to determine whether a license is necessary. It is important to note that running advertising campaigns and officially cashing︀ out earned crypto may be difficult without a license.