Ozonetel provides off-the-shelf business communication and contact center solutions on the cloud.
KooKoo (http://www.kookoo.in) exposes a set of telephony APIs (like Twilio).
BizPhone (http://www.bizphone.in) allows you to build and manage your own efficient business communication solution (like Grasshopper.com).
Cloudagent (http://www.cloudagent.in) provides contact center services in the cloud.
After disrupting the voice market in India, hoping to disrupt contact center market in the US
Cloudagent has reinvented the call center market in India. Currently handling more than a million call center minutes per day with enterprises like Intuit, Wipro and startups like Zovi, Bigbasket using it for their call center operations.