Through the acquisition of Unisphere, in 2002, the company entered the market for edge routers, which are used by ISPs to route internet traffic to individual consumers.

Pradeep Sindhu,[6] a scientist with Xerox's Palo Alto Research Center (PARC),[7] conceived the idea for Juniper Networks while on vacation in 1995[8] and founded the company in February 1996.

[14] About seven months after the company's founding, Scott Kriens was appointed CEO to manage the business, while founder Sindhu became the Chief Technology Officer.

[16] Later that year, Juniper Networks raised an additional $40 million in investments[17] from a round that included four out of five of the largest telecommunications equipment manufacturers: Siemens, Ericsson, Nortel and 3Com.

[29] According to Telephony, Juniper Networks became the "latest darling of Wall Street",[30][31] reaching a $7 billion valuation by late July.

[23][31] According to Businessweek, "analysts unanimously agree[d] that Juniper's boxes [were] technically superior to Cisco's because the hardware does most of the data processing.

[8][10] Cisco had grown through acquisitions to be a large generalist vendor for routing equipment in homes, businesses and for ISPs, whereas Juniper was thought of as the "anti-Cisco" for being a small company with a narrow focus.

[6][33][34] In January 2001, Cisco introduced a suite of router products that Businessweek said was intended to challenge Juniper's increasing market-share.

[23] By 2002, both companies were repeatedly announcing products with faster specifications than the other in what Network World called a "'speeds-and-feeds' public relations contest".

[38][39] In late 2000, Juniper formed a joint venture with Ericsson to develop and market network switches for internet traffic on mobile devices,[40][41] and with Nortel for fiber optic technology.

[8][43]: 12  Juniper's growth slowed in 2001 as the telecommunications sector experienced a slowdown[44] and revenues fell by two-thirds during the dot-com bust.

[53][54] Juniper stockholders alleged the company engaged in deceptive backdating practices that benefited its top executives unfairly.

[74] In May 2014, Palo Alto Networks agreed to pay a $175 million settlement for allegedly infringing on Juniper's patents for application firewalls.

[75] In 2015, Wired magazine reported that the company announced it had found unauthorized code that enabled backdoors into its ScreenOS products.

[78] The acquisition was blocked by the U.S. Department of Justice in January 2025, citing concerns about reduced competition and innovation, leading to higher prices for consumers.

[94] In April 2019, Juniper acquired wireless LAN (WLAN) startup Mist Systems to bolster its software-defined enterprise portfolio and multicloud offerings.

[95] In February 2022, it was announced Juniper had acquired WiteSand, a specialist cloud-native zero trust network access control (NAC) solutions company.

[43]: 8 [108] It incorporated specialized application-specific integrated circuits (ASIC) for routing internet traffic that were developed in partnership with IBM.

[115] In April 2002, Juniper released the first of the T-series family (originally known under the code-name Gibson), which could perform four times as many route lookups per second as the M160.

[122] In 2003, Juniper entered the market for cable-modem termination systems with the G-series product family after the acquisition of Pacific Broadband.

[129] In December 2014, Juniper introduced a network switch, OCX1100, that could run on either the Junos operating system or the Open Compute Project open-source software.

The gateways sold well, but customers and resellers reported a wide range of technical issues starting in 2010, which Juniper did not acknowledge until 2012, when it began providing updates to the product software.

"[155] In December 2015, Juniper Systems announced that they had discovered "unauthorized code" in the ScreenOS software that underlies their NetScreen devices, present from 2012 onwards.

The following month Juniper announced its SDN strategy, which included a new licensing model based on usage and new features for the Junos operating system.

[157] In February 2013, Juniper released several SDN products, including the application provisioning software, Services Activation Director and the Mobile Control Gateway appliance.

[129] Every year, since 2009, Juniper holds SDN Throwdown competition to encourage students from universities across the world to access NorthStar Controller and build a solution around it to optimize network throughput.

[165] In October 2018, Juniper announced a new offering called EngNet, which is a set of developer tools and information meant to help companies move toward automation, and replace the typical command-line interface.

Juniper sells directly to businesses, as well as through resale and distribution partners, such as Ericsson, IBM, Nokia, IngramMicro and NEC.

[167] According to a 2013 report by Glassdoor, Juniper Networks has the highest paid software engineers in the technology sector by a margin of about $24,000 per year.

[168] It operates the Juniper Networks Academic Alliance (JNAA) program, which scouts fresh college graduates.