Signal messaging service

Signal is a cross-platform centralized encrypted instant messaging service developed by the Signal Technology Foundation and Signal Messenger LLC. It was founded in its current form in 2018, though its technical lineage dates back to Whisper Systems, a startup co-founded by security researcher Moxie Marlinspike in 2010. After Whisper Systems was briefly acquired by Twitter (now X), Marlinspike transitioned the project into a collaborative open-source effort through Open Whisper Systems.

The modern Signal era began when WhatsApp co-founder Brian Acton left Meta (formerly Facebook) over privacy disagreements and provided a $50 million loan to establish the Signal Technology Foundation as a 501(c)(3) nonprofit. This structure ensures that the platform is not beholden to corporate investors or advertising revenue, prioritizing user privacy and security over profit. The software is developed in the United States, specifically in Mountain View, California, though as an open-source project, its code is scrutinized and contributed to by a global community of developers.

As of 2026, Signal remained a critical tool for journalists, activists, and privacy-conscious users worldwide. It is governed by a board that includes prominent tech figures such as Meredith Whittaker and Brian Acton. Its business model relies entirely on individual donations and grants rather than data monetization or traditional ownership stakes.