For some time we've noted that SOAP is losing to REST and REST-like approaches. In fact, in most sectors, it's already lost. 68% of the APIs in our directory are REST, while 19% are SOAP. But one area where SOAP has remained popular is the enterprise. Anecdotally, this may be changing, based on recent announcements, such as from the Cicero API.
Azavea will continue supporting the previous version of the Cicero API for at least one year from April 1st, 2012, but will be encouraging users to transition to using the new REST API to access district-matching and elected official lookups before then. The new Cicero API will support programmers seeking to use JSON and the convenient querying capabilities inherent in a RESTful interface.
The choice of REST/JSON combination is par for the course with startups and other individual-focused API providers. But SOAP is still seeing wide use in enterprises, where there are tools to make SOAP much less complicated. And the enterprises rely on these tools, such as a .NET environment, for all development. Accessing or creating SOAP services with these tools is essentially drag-and-drop.
Still, others are making the switch. A secure faxing service announced its REST API yesterday, noting that it is "superior to the old SOAP-based system in a number of ways."
A trailblazer of software-as-a-service in the enterprise, Salesforce added a REST API in October 2010. One could point to that as the start of the trend--if it is a trend.
With APIs as a whole, enterprise has been slow to adopt. But that is changing, as we're seeing more traditional companies launch APIs. It makes sense the these organizations would also eventually follow the best practices of the nimbler tech leaders.