Session (software)

Session

Company type	Nonprofit
Industry	Instant messaging software, Privacy software
Founded	2018
Founder	Oxen Privacy Tech Foundation
Headquarters	Switzerland
Area served	Worldwide
Products	Session instant messaging app
Parent	The Session Technology Foundation

Session is an instant messaging app designed for multiple platforms that prioritizes user privacy and anonymity through end-to-end encryption. Created by the nonprofit organization The Session Technology Foundation, it utilizes a decentralized network based on blockchain technology to facilitate message delivery. The service supports both individual and group chats, allowing users to share files, voice recordings, images, and videos.

Applications for Session are available on desktop operating systems including macOS, Windows, and Linux, as well as mobile devices running iOS and Android.

Features

Account registration on Session does not require linking a phone number or email; instead, users receive a randomly generated 66-character alphanumeric identifier for identification purposes. All forms of communication—messages, audio notes, pictures, and documents—are secured with end-to-end encryption using the Session protocol. Originally, the platform operated over the Loki blockchain network. Its security measures were independently audited by Quarkslab in 2021. By 2025, Session migrated to its own open-source, decentralized blockchain called the Session Network, purpose-built to handle encrypted data transmission for the messenger.

Development

The project began development in 2018 under the Australia-based Oxen Privacy Tech Foundation. Initially forked from Signal, Session evolved to implement its proprietary "Session Protocol" due to concerns about Signal’s centralized infrastructure and metadata retention practices. This shift was aimed at improving anonymity and decentralization, resulting in extensive modifications during development.

In 2024, responding to increasing privacy regulations and surveillance legislation in Australia, the development and publishing duties were transferred to the Switzerland-based Session Technology Foundation.

Limitations

Session currently does not provide support for two-factor authentication, and its core protocols are still under active development. Since replacing the Signal Protocol with its own protocol, certain features such as forward secrecy and deniable authentication have yet to be integrated.