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If you've spent any time on VATSIM, you likely know that the network is built on top of a piece of software called the Flight Simulator Daemon, or FSD. FSD is the core of the VATSIM network, and is responsible for managing all the connections between pilots and controllers.

If you've been paying attention, you may have noticed that FSD is not listed in the API Overview. FSD's primary purpose is to manage connections between pilots and controllers, and it does not provide any public APIs. The Data API provides access to FSD's data, but does not provide any method of interaction with FSD itself.

If you're interested in developing software that interacts with FSD, please contact [email protected] to discuss your project. Upon approval, you will be granted access to the FSD protocol documentation and other resources.

Please explore the rest of the documentation to learn more about the VATSIM APIs that are available to the public.