Jordan Ritter (born February 1, 1978) is an American serial entrepreneur, software architect and angel investor. He is best known for his work at Napster, the file-sharing service he co-founded along with Shawn Fanning and others. His time at Napster was documented in Joseph Menn's book All the Rave: The Rise and Fall of Shawn Fanning's Napster and Alex Winter's film Downloaded.

Jordan Ritter was born in Northridge, California and grew up in Texas and Florida. Ritter skipped the 5th grade when he was 10, and later went on to graduate from the International Baccalaureate Program at Hillsborough High School. Ritter attended college at Lehigh University on scholarship, starting as a sophomore and pursuing a double major in music and computer science. He dropped out in 1998, relocating to Boston, Massachusetts to begin his career in computer security.

Ritter started out in the computer security industry, working as a paid hacker for the Boston office of Israeli computer security company Netect. While his main focus was probing major software and online systems for vulnerabilities, he also fixed code and conducted security audits for the company's own software HackerShield.

During his tenure, Ritter discovered and published several serious security vulnerabilities, including an anonymous, remote administrative privilege escalation in Washington University's FTP server. At the time, this affected approximately 80% of all computers on the Internet.

Early in 1999, Netect was purchased by BindView. Ritter was retained in the acquisition.

While working for BindView, Ritter met Shawn Fanning online through an IRC channel for computer hackers called #!w00w00. In May 1999, Fanning began soliciting Ritter and several other w00w00 members for help.

Since Fanning initially refused to allow inspection of the source code, members took this as a challenge and began reverse-engineering various aspects of the service. Ritter and fellow w00w00 member Seth McGann focused on the protocol and backend software, identifying bugs and proposing likely fixes to Fanning, while w00w00 member Evan Brewer managed the system that the server ran on. In early June 1999, Fanning asked Ritter to fully take over development of the server while Fanning focused on the Windows client. Two months later, Yosi Amram invested $250,000 in Napster and required that company operations relocate from Massachusetts to California. Ritter moved to Silicon Valley in September 1999, initially sharing an apartment with Fanning and Sean Parker at the San Mateo Marriott Residence Inn.

Ritter was directly responsible for many of the key evolutions of the backend service architecture during Napster's period of hyper-growth, including its novel load-balancing system, MySQL and subsequent Oracle database integration, and transparent full-mesh server linking. In addition to leading the backend team, Ritter also managed production systems deployment and network security, database systems and supporting infrastructure, and served as primary public contact point for all security-related issues concerning the service and operations. Ritter also oversaw the Moderator Community, a group of individuals who volunteered their free time to help moderate the various socially-focused portions of the Napster service.