IoT the term refers to the connection of devices (the Things) through the internet so they can collect and share data without human assistance.
The adoption of IoT within the industry has opened up unlimitted possibilities and are rapidly redefining all areas of business operations. Pioneering companies are connecting complex physical machinery with data analytics, bringing unforeseen insights, increasing efficiency and opening up a new era of competitiveness and growth.
Some of the major IoT platforms are listed below
Google Cloud IoT
AWS IoT Core
Microsoft Azure IoT
IBM Watson IoT
Bosch IoT Suite
Oracle IoT cloud platform
Above has given you IoT Platform companies list , To more about Top IoT platform Companies features refer http://www.thetips4you.com/iot-platform-companies/
There are free IoT platforms available also like
Kaa IoT platform