Session - Free and Open-Source E2E Decentralized Cross Platform Messaging
Universal Apps
For anyone looking for an anonymous messaging system, that
requires no account, email or telephone number to set up, Session may be what you are looking
for. With clients for macOS, iOS, Windows, Android and Linux, you can
communicate with just about anyone through a network of 2000
decentralized servers. If a server goes down, the network stays up,
eliminating any one node as a single source of failure.
Session's encrypted messages are sent through an onion routing network. Onion networks encrypt messages with multiple layers of encryption, then send them through a number of nodes. Each node ‘unwraps’ (decrypts) a layer of encryption, meaning that no single node ever knows both the destination and origin of the message. Session uses onion routing to ensure that a server which receives a message never knows the IP address of the sender.
Account in Session are created and secured with a mnemonic seed which can be used to restore your existing Account ID to a new device. Your display name can be anything you want it to be. Session does not collect any geolocation data, metadata, or any other data about the device or network you are using. On your local device, Session allows you to encrypt your local Session database with a PIN code. With this feature turned on, your messages cannot be accessed without knowing your PIN code. If the police or a thief have physical access to your device, they still can't see your messages without your PIN.
Voice and video messaging are current beta features in the app. In early 2025, the back end technology for the app is transitioning to upgraded technology, using crypto-based engineering. Although there are no paid features currently, the non-profit foundation behind the app says that it may implement some in the future, using cryptocurrency. They say the primary private messaging will always be free.