tcpdump - tcpdump is a common packet analyzer that runs under the command line.
Postman - The Collaboration Platform for API Development
SmartSniff - SmartSniff is a packet sniffer that capture TCP/IP packets and display them as sequence of conversations between clients and servers.
Sauce Labs - Test mobile or web apps instantly across 700+ browser/OS/device platform combinations - without infrastructure setup.
netcat - Netcat is a featured networking utility which reads and writes data across network connections...
TestComplete - TestComplete Desktop, Web, and Mobile helps you create repeatable and accurate automated tests across multiple devices, platforms, and environments easily and quickly.