Moxie Marlinspike

Marlinspike began his career working for several technology companies, including enterprise infrastructure software maker BEA Systems Inc.

In 2010, Marlinspike was the chief technology officer and co-founder of Whisper Systems, an enterprise mobile security startup company. In May 2010, Whisper Systems launched TextSecure and RedPhone. These were applications that provided end-to-end encrypted SMS messaging and voice calling, respectively. Twitter acquired the company for an undisclosed amount in late 2011. The acquisition was done "primarily so that Mr. Marlinspike could help the then-startup improve its security". During his time as Twitter's head of cybersecurity, the firm made Whisper Systems' apps open source.

Marlinspike left Twitter in early 2013 and founded Open Whisper Systems as a collaborative open source project for the continued development of TextSecure and RedPhone. At the time, Marlinspike and Trevor Perrin started developing the Signal Protocol, an early version of which was first introduced in the TextSecure app in February 2014. In November 2015, Open Whisper Systems unified the TextSecure and RedPhone applications as Signal. Between 2014 and 2016, Marlinspike worked with WhatsApp, Facebook, and Google to integrate the Signal Protocol into their messaging services.

In 2017, Marlinspike assisted the cryptocurrency company MobileCoin as an early technical advisors alongside fellow former DARPA researcher Todd Huffman. MobileCoin was designed to be the in-app payments for Signal and Mixin Messenger.

On February 21, 2018, Marlinspike and WhatsApp co-founder Brian Acton announced the formation of the Signal Technology Foundation and its subsidiary, Signal Messenger LLC. Marlinspike served as Signal Messenger's first CEO until stepping down on January 10, 2022.

In the wake of the United States government group chat leak Marlinspike posted in March 2025: "There are so many great reasons to be on Signal. Now including the opportunity for the vice president of the United States of America to randomly add you to a group chat for coordinating sensitive military operations. Don't sleep on this opportunity..."

Late 2025 Marlinspike made Confer which was introduced to the general public beginning of 2026. Confer is a private AI assistant with a focus on end-to-end encryption and verifiable privacy. It makes use of passkeys to encrypt chats on the device, making sure prompts and responses cannot be read by anyone.

Originally from the state of Georgia, Marlinspike moved to San Francisco in the late 1990s at age 18. The name Moxie Marlinspike is an assumed name partly derived from a childhood nickname.

Marlinspike is a sailing enthusiast and master mariner. In 2004, he bought a derelict sailboat and, with three friends, refurbished it and sailed around the Bahamas while making a "video zine" about their journey called Hold Fast. He is also an anarchist, and several of his essays and speeches are published on the website The Anarchist Library, including "An Anarchist Critique of Democracy" and "The Promise of Defeat."

Mobily surveillance controversy

In 2013, Marlinspike published emails on his blog that he claimed were from Saudi Arabian telecom service Mobily soliciting his help in surveilling their customers, including intercepting communications running through various applications. Marlinspike refused to help, making the emails public instead. Mobily denied the allegations. "We never communicate with hackers", the company said.