Lately I have observed significant movement in two transformational trends - adoption of REST over SOAP and proliferation of non-relational persistence options. These two trends complement each other and they are likely to cause disruption sooner than later.
The enterprise software that required complex transactions, monitoring, and orchestration capabilities relied on the SOAP-based architecture and standards to realize their SOA efforts. The consumer web on the other side raced towards embracing RESTful interfaces since they were simple to set up and consume. There are arguments on both the sides. However, lately the market forces have taken the side of REST even if REST has significant drawbacks in the areas such as security and transactions. This once again proves that a simple and good enough approach that conforms to loose contracts outweighs a complex solution that complies to stricter standards even if it means compromising certain critical features. The web is essentially an unreliable stateless medium and any attempts to regulate it is less likely to work in our favor.
Many argue that the self-describing standards for SOAP are its strength over the RESTful services that lacks such features. However designing a RESTful service is fairly trivial since it allows to learn and experiment by being iterative unlike a relatively complex upfront learning process associated with the SOAP-based architecture. There has been a flurry of activities in the messaging middleware by Google that makes these RESTful interface even more compelling. This includes Google Wave Federation and PubSubHubbub. The developers are more likely to prefer these messaging protocols against SOAP and that would mean more RESTful APIs in the Pushbutton Web. Easy consumability reduces the initial adoption barrier and that's the key to success in many cases.
Since I last blogged about the continuum of the database on the cloud from schemaless to full-schema new persistence options have emerged such as RethinkDB and HadoopDB and many debates have spurred questioning the legacy of the RDBMS. For a cloud-like environment the statelessness, ad hoc persistence design, and instantaneous horizontal scale go well with the RESTful architecture. The growing popularity of SimpleDB and CouchDB along with many discussions on how to achieve CRUD with REST signal that the persistence is becoming more RESTful and schemaless.
I was convinced quite some back that REST was certainly the future for the consumer web but the latest trends have made me believe that the REST will see its adoption in the enterprise software accelerated much sooner than I had originally expected. This is like Java and Internet; the organizations embraced Java and the Internet at the same. The same will be true for the cloud and REST. When the companies consider moving to the cloud they will reconsider their SOA and persistence strategy and will likely adopt REST and alternate persistence models.
The cloud might be the last nail in the SOAP coffin.