REST: Architecture for the Scalable Web

#A Dissertation That Shaped the Industry

In 2000, Roy Fielding — one of the principal authors of HTTP — published his doctoral dissertation at UC Irvine. Chapter 5 described “Representational State Transfer” (REST), an architectural style for distributed hypermedia systems. It wasn’t a new protocol or framework — it was a set of constraints that, when followed, made web systems scalable and evolvable.

#The Constraints

1. Client-Server — separate concerns between UI and data storage
2. Stateless — each request contains all information needed to process it
3. Cacheable — responses must declare themselves cacheable or not
4. Uniform Interface — resources identified by URIs, manipulated through representations
5. Layered System — intermediaries (proxies, gateways) can be inserted transparently

#The API Revolution

REST gave the industry a shared vocabulary for building web APIs. Instead of SOAP envelopes and WSDL files, you had resources, HTTP verbs, and status codes. It was simple enough to explain on a whiteboard and powerful enough to power the API economy.