In Brief

Founded in 2004, OnSIP is a leading provider of real-time communications (RTC) services to over 40,000 businesses. OnSIP® Business VoIP customers enjoy the benefits of an on-demand phone system without the traditional high cost, burden, and inflexibility. The company also offers a cloud platform and simple APIs for developers to rapidly and affordably build RTC applications of their own.

Sometimes we are asked, “Who is Junction Networks?” Junction Networks is our founding company name. OnSIP is our product/service. It just so happens that OnSIP is catchier, so we typically use it in most places!

Read our "OnSIP at a Glance" Overview

Download PDF

Principals and Management

Mike Oeth OnSIP Rob Wolpov OnSIP John Riordan OnSIP

Mike Oeth
Cofounder & CEO

Rob Wolpov
Cofounder & President

John Riordan
Cofounder & CTO

Mike Oeth graduated from Harvard College in 1991 with a degree in Economics and went to work for a software company, FactSet, based in Greenwich, CT. Since then, he has held varying leadership positions at technology companies, including VP of Sales at Interport Communications, VP of Product Development at RCN, CTO at LivePerson, and National Account Manager at AboveNet. In 2013, Mike was awarded a Gold Stevie® Award in the Executive of the Year - Telecommunications category at The 11th Annual American Business Awards. That same year, he was listed as the #5 most influential person in VoIP by

Rob Wolpov holds his M.B.A from Columbia University. He received a B.S. from the Wharton School of Business at the University of Pennsylvania. He began his career as a software engineer for the Frustum Group, a provider of leading foreign exchange trading software. He has planned and launched multiple technology ventures including Nemex, Inc. and ASP Junction, which was purchased by LivePerson, Inc. Before forming Junction Networks, Rob worked as a consultant in the Financial Services practice for IBM Business Consulting Services, advising some of the largest financial institutions today.

John Riordan studied computer science and cognitive science at MIT in the late 80s. After school, he spent a few years doing software engineering on Wall Street, jumping into the Internet in 1994. He founded one of the largest Internet Service Providers in New York City, Interport, before it was purchased by RCN. Since that time, he’s continued to be an Internet entrepreneur and engineer. In 2014, John was named a WebRTC Technology Pioneer by TMC at the WebRTC Conference and Expo.


OnSIP Careers

OnSIP is growing and has open positions. As a bootstrapped software company, we maintain a fast-paced ‘startup’ environment while respecting work-life balance. We like technology and making customers happy.

Available Positions:

If you would like to contact us about an open position, please send a cover letter and resume to or click on one of the positions above to get in touch.

What's New at OnSIP?

See Our Recent Press

Let us help you find the right phone
service for your business.