John Sung Kim

Founder & CEO JetBridge

Last Reviewed: September 19, 2026

Executive Summary

John Sung Kim is a serial software founder whose first company, Five9, helped create the cloud contact centre category and eventually listed on Nasdaq. He founded it in 2001, when running call-centre software as a hosted service was still an unproven idea, and left before the company reached the scale it is known for today. His second venture, DoctorBase, took a deliberately capital-light path through the crowded digital health market and was acquired by Kareo in 2015 with roughly 18,000 physicians on the platform. He now runs JetBridge, an engineering staffing firm built around an unusual hiring premise — that live pair-programming interviews, rather than résumés or algorithm puzzles, are the only reliable way to assess an engineer — and places AI and data engineers with US companies including eBay, Compass, HP and LabCorp. Alongside the operating work he is an early-stage angel investor with positions in SpaceX, Rappi and Lvl5, and a regular writer on startup operations for TechCrunch, Forbes and Medium.

Career Highlights

• Founded Five9 in 2001, widely described as the first cloud-based contact centre platform; the company later listed on Nasdaq as FIVN.
• Founded and served as chief executive of DoctorBase, reaching roughly 18,000 doctors and close to 9 million patients before its sale.
• Ran DoctorBase to profitability before raising outside money, taking only about $500,000 via AngelList, and exited against competitors with many times its funding.
• Sold DoctorBase to Kareo in March 2015; Kareo has since become Tebra.
• Founded JetBridge and built its screening around live pair-programming interviews, with a two-week risk-free trial for clients.
• Advised venture-backed companies including oDesk, RingCentral, Qualys, 6connect and LGC Wireless.
• Early angel investor in SpaceX, Rappi, Lvl5 (acquired by DoorDash) and Juice Labs (acquired by HP).

Professional Journey

Kim graduated from Penn State University in 1997 with a degree from the College of the Liberal Arts — a background he has used publicly to argue that technical founders are not the only people who can build software companies. Four years later he started Five9. The idea was to deliver call centre software as a hosted service at a moment when the incumbent products were on-premises systems sold with hardware and long implementation projects. Kim has told the origin of the name against himself: publicly it stood for 99.999% reliability, privately for his own height. He led the company in its early years; it went on under later chief executives to grow substantially, raise more than $80 million in venture capital, and go public on Nasdaq.

His second company inverted the funding logic of the first. DoctorBase built patient-communication tools for small medical practices, a market crowded with better-capitalised startups. Kim’s approach was to reach profitability before raising, and he has said the company took only about $500,000 through AngelList after it was already making money. By the time Kareo announced its acquisition in March 2015, DoctorBase connected roughly 18,000 physicians with nearly 9 million American patients. Kareo folded the product into its practice-management suite and later became part of Tebra. Kim wrote publicly about the experience afterwards, including a TechCrunch piece on why digital health startups fail, arguing that regulatory complexity was less fatal than the mismatch between venture funding expectations and healthcare sales cycles.

Between and around the operating roles he advised a series of venture-backed companies — oDesk, RingCentral, Qualys, 6connect and LGC Wireless among them — and built an angel portfolio that includes SpaceX, Rappi, Lvl5 (later acquired by DoorDash) and Juice Labs (later acquired by HP).

JetBridge, his current company, is a staffing business rather than a software product, and its distinctiveness is procedural. Where most technical recruiting relies on résumé screens and take-home exercises, JetBridge hires engineers only through live pair-programming interviews, and offers clients a two-week risk-free trial on any placement. The firm recruits internationally — Kim writes frequently about how offshore and nearshore developers are treated by the companies that employ them — and now positions itself specifically around AI and data engineering. Its client list includes Invitae, eBay, Compass, HP, LabCorp and METR.

Education

Pennsylvania State University

Bachelor’s degree, College of the Liberal Arts, 1997. The specific major is not stated in any public source.