Linked Data and Linked APIs: Similarities, Differences, and Challenges

In an often retweeted Twitter post, entrepreneur and software architect Inge Henriksen described the relation of Web 1.0 to Web 3.0 as: “Web 1.0 connected humans with machines. Web 2.0 connected humans with humans. Web 3.0 connects machines with machines.” On the one hand, an incredible amount of valuable data is described by billions of triples, machine-accessible and interconnected thanks to the promises of Linked Data. On the other hand, rest is a scalable, resource-oriented architectural style that, like the Linked Data vision, recognizes the importance of links between resources. Hypermedia apis are resources, too—albeit dynamic ones—and unfortunately, neither Linked Data principles, nor the rest-implied self-descriptiveness of hypermedia apis sufficiently describe them to allow for long-envisioned realizations like automatic service discovery and composition. We argue that describing inter-resource links—similarly to what the Linked Data movement has done for data—is the key to machine-driven consumption of apis. In this paper, we explain how the description format restdesc captures the functionality of apis by explaining the effect of dynamic interactions, effectively complementing the Linked Data vision.