Nokia OS (NOS) is an informal name for the operating system in many Nokiamobile phones. Nokia OS is not a trademark or brand name, and there is no such product as "Nokia OS" or "NOS", though the term "Nokia OS" is used in official Nokia communications. The overall software architecture in many feature phones that use NOS is referred to as the ISA (Intelligent Software Architecture) platform. It is a proprietary platform for Nokia's internal use only and is not licensed to third party vendors. There is no public documentation available. No direct application programming interface (API) is provided, but most ISA phones can be programmed with Java Platform, Micro Edition (Java ME). It is sometimes called[by whom?] the "domestic OS".