The Elite: Dangerous Data Network (EDDN) is a system for players to share dynamic data - such as commodity prices - from Elite: Dangerous.
The Elite: Dangerous Data Network is a system for willing Commanders to share dynamic data about the galaxy with others. By pooling data in a common format, tools and analyses can be produced that add an even greater depth and vibrancy to the in-game universe.
EDDN is not run by or affiliated with Frontier Developments. Hosting has been very generously provided by Vivio Technologies.
Further details are available on the wiki, and source is available on Github.
EDDN has an HTTP REST API for uploaders and a ZeroMQ API for data users.