RouteRabbit team has extensive experience in leveraging external APIs to rapidly deliver software functionality. We have experience with both REST and SOAP APIs although service providers are mostly exposing REST APIs. We prefer to use JSON over XML due to parser support and whenever SSL support is available, we take advantage of it.
Many APIs have restrictions such as a number of concurrent requests allowed and volume restrictions – we understand the implications of such constraints — we have experience in mitigating impact of such constraints on applications we develop, by programmatically monitoring usage and building workarounds to handle such constraints.
We have already experimented with APIs like Google Map, Stripe, MapQuest, Google, Facebook, Wit.ai, api.ai, SendGrid, Neutrino, Twilio for features like Map, Payment Gateway, Open Authentication, Voice Enabled Apps, Geocoding, SMS, Call and Email integrations.