SimpleX Network

Decentralized Application

A messaging network, and the SimpleX Chat apps built on it, that uses no user identifiers of any kind: no phone number, username or account ID. Two people connect through one-time invitation links or QR codes, and each conversation runs over separate, unidirectional message queues held on relay servers (SMP servers), with files on separate file servers (XFTP). Relays see only queue addresses, not who is talking to whom, and only the client devices hold information about users, contacts and groups, which the project says avoids the metadata exposure of federated networks. Messages use double-ratchet end-to-end encryption with an additional encryption layer. Anyone can run a relay, and the apps ship with preset relay operators, including SimpleX Chat Ltd and Flux. The apps run on iOS, Android and desktop, and there is a terminal app .

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Details

License Copyleft (AGPL-3.0). The SimpleX and SimpleX Chat names and logos are covered by a separate trademark policy and assets licence. https://github.com/simplex-chat/simplex-chat (apps and chat core); https://github.com/simplex-chat/simplexmq (relay server and protocols)
Dev Status 🟢 Active
Owner SimpleX Chat Ltd (named in the project's privacy policy as an operator of the preset relay servers and the notification servers); the code is published under the simplex-chat GitHub organisation
Governing Body SimpleX Chat Ltd; no external governance body is described
Country United Kingdom (SimpleX Chat Ltd is registered in London, per its privacy policy)
Start Year 2019
Stack Haskell, Kotlin, Swift and TypeScript (the repository's main languages); SimpleX Messaging Protocol (SMP) servers, an XFTP file protocol, a chat protocol and a whitepaper; double-ratchet encryption
Funding Investment (the project reports an investment from Jack Dorsey and Asymmetric in August 2024 and a Wefunder crowd-investment campaign) and donations
Last Investigated Oct 29, 2026

Use Case Domains

Communication Platform Evolution & Sovereignty

Affordances

End-to-end encrypted Self-hostable Protocol federation

Decentralized Application Attributes

Origins Messaging with no user identifiers, built so that the network cannot see who communicates with whom, rather than merely hiding message content; the project's stated aim is the first messaging platform without user identifiers
Database Data lives on each device; relay servers hold queued messages only until delivery, per the project's description of its design
Query Language N/A
Data Formats SimpleX Messaging Protocol and chat protocol messages, with the formats given in the project's protocol documents and whitepaper
Collaborative Live Editing N/A
Rich Text Editing Not stated by the project.
Mobile Support Yes: iOS (App Store and TestFlight) and Android (Google Play and APK)
Web Support No: the README describes mobile, desktop and terminal apps and no web app
Native Apps Yes: iOS, Android and desktop apps
Terms Free to use; AGPL-3.0 source; the project asks for donations
Funds Not stated by the project.
Based On The double-ratchet algorithm (as used by Signal) with an additional encryption layer; unidirectional message queues and a custom relay protocol
Use Case Category Private messaging, group chat and calls
User Interface Type Mobile and desktop apps, plus a terminal (command-line) app
Offline Capabilities Messages are queued on relay servers until the recipient connects; there is no offline or local-network mode in the cited sources
Collaboration Features Direct chats, groups, voice and video calls, file transfer
Data Portability Local database export is provided by the apps (the project documents managing data and migrating to a new device); there is no account to port
Integration Ecosystem A published chat protocol, documented in the project's reference section
Web2 Data Export Not stated by the project.
Prosocial Coherence Not stated by the project.
Economic Flows None: no payment, token or marketplace feature.
Governance & Decision Making Decided by the company; development is open and contributions are invited through GitHub
Media / Publishing N/A
Knowledge Management N/A
Sensemaking N/A
Project Management N/A
Communication Model Asynchronous messaging through relay servers using separate unidirectional queues per connection; peers do not share a user identifier
Network Resilience Relays can be run by anyone and a client can use several relay operators; the default relays are run by SimpleX Chat Ltd and Flux, and iOS push notifications currently go through SimpleX Chat Ltd's servers
Discovery Mechanism None by design: contacts are added by one-time links or QR codes; the project's documentation also lists a SimpleX Directory service
Max Participants Not stated by the project.
Data Sovereignty High for content and contacts, which stay on user devices; relays hold only transient encrypted queues