The history of Signal Foundation is closely tied to the history of Signal, the encrypted messaging application.
Signal's origins trace to 2010, when Moxie Marlinspike and Stuart Anderson founded Whisper Systems, a company that developed encrypted communication tools for Android. Whisper Systems was acquired by Twitter in 2011, and Marlinspike worked at Twitter for a period before leaving to continue developing secure communication tools.
In 2013, Marlinspike founded Open Whisper Systems, a non-profit software development group that developed TextSecure (encrypted SMS) and RedPhone (encrypted voice calls). These applications were later merged into Signal in 2014.
The Signal Protocol, developed by Marlinspike and Trevor Perrin, became the foundation for Signal's end-to-end encryption. The protocol was notable for its mathematical elegance and security properties, and was subsequently adopted by WhatsApp (2016), Facebook Messenger (2016), Google Messages, and other major messaging platforms.
In February 2018, Signal Foundation was established by Moxie Marlinspike and Brian Acton. Acton had co-founded WhatsApp in 2009 and sold it to Facebook in 2014 for approximately $19 billion. Acton left Facebook in 2017, reportedly over disagreements about monetizing WhatsApp users' data. He committed $50 million (later increased to $100 million) to establish Signal Foundation, providing the organization with long-term financial stability.
The foundation was created to address the challenge of maintaining a privacy-focused messaging service without the commercial pressures that typically drive technology companies. By operating as a non-profit, Signal Foundation could prioritize user privacy and security over profit maximization.
In 2018, Signal Foundation established Signal Messenger LLC as a subsidiary to handle the technical development and maintenance of the Signal application and protocol. This structure allows the foundation to focus on its mission while the LLC handles operational aspects.
In January 2021, Signal experienced a massive surge in new users following WhatsApp's announcement of changes to its privacy policy that would allow more data sharing with Facebook. Signal gained tens of millions of new users in a matter of days, briefly overwhelming the service's infrastructure.
Moxie Marlinspike stepped down as CEO of Signal Messenger in January 2022. Meredith Whittaker was appointed President of Signal Foundation in 2022, taking on a leadership role at the organization.
In 2024, Signal introduced several new features including usernames (allowing users to communicate without sharing their phone numbers), improved group calling, and enhanced privacy features.