Telcos are traditionally closed but must open APIs to adapt to changing customer expectations and new competitive threats. They have many potential APIs around communications, networks, and user data that could be offered. Current models include wholesaling APIs to aggregators or directly to developers. While opening APIs could diversify revenue and allow telcos to focus on core strengths, there are also risks around revenue declines and commoditization that must be addressed. Developer programs are starting to resemble those of internet companies but telcos still have questions around APIs and their business models.