Citrix Systems, Inc. is an American multinational software company founded in 1989 that provides server, application and desktop virtualization, networking, software-as-a-service, and cloud computing technologies. The company began by developing remote access products for Microsoft operating systems. It licensed source code from Microsoft and has been in partnership with the company throughout its history. Citrix came to prominence in the 1990s as a leader in thin client technology. Through several acquisitions in the mid-2000s, the company expanded into server and desktop virtualization, as well as cloud and Infrastructure as a Service.
Zscaler is a global cloud-based information security company that provides Internet security, web security, next generation firewalls, sandboxing, SSL inspection, antivirus, vulnerability management and granular control of user activity in cloud computing, mobile and Internet of things - centric environments. As of 2015, Zscaler provides automated threat forensics and dynamic malware protection against advanced cyber threats, such as advanced persistent threats and spear phishing for more than 6,000 corporate, government and military organizations with more than 15 million paying users.