A link contract is an approach to data control in a distributed data sharing network.
Link contracts are a key feature of the XDI specifications under development at OASIS.
Unlike a conventional Web link, which is essentially a one-dimensional "string" that "pulls" a linked document into a browser, a link contract is a graph of metadata (typically in JSON) that can actively control the flow of data from a publisher to a subscriber by either "push" or "pull".
Using this design, the vast majority of link contracts can be very simple, referring to a very small number of more complex link contracts that have been carefully designed to reflect the requirements of common data exchange scenarios (e.g., business cards, mailing lists, e-commerce transactions, website registrations, etc.)
Link contracts have been proposed as a key element of digital trust frameworks such as those published by the non-profit Open Identity Exchange.