SimpleX Chat is an open-source (AGPLv3) end-to-end encrypted messenger developed by SimpleX Chat Ltd, a UK private limited company (Companies House 13691484) whose director and 75%-plus shareholder is founder Evgeny Poberezkin. Its privacy policy (updated April 18, 2026) states the messaging protocol assigns no user profile identifiers of any kind — not phone numbers, usernames, keys or hashes — that profiles and message history live only on the user's device, and that relay servers cannot read message content or size; the same policy documents what preset relays and the iOS notification server can still observe (device push tokens and queue counts, temporary anti-abuse IP storage, encrypted undelivered messages held up to 21 days) and that preset relays are run by SimpleX Chat Ltd plus opt-in third-party operator Flux. The company discloses VC funding — roughly USD 370,000 pre-seed via Village Global and angels, then a USD 1.3 million round led by Jack Dorsey with Asymmetric Capital Partners — described as carrying no board seat or control provisions, and has announced but not yet formed a SimpleX Network Foundation/Consortium. Warts: a VC-funded commercial operator, no account recovery (lost device without backup means lost data), no bug bounty, and reproducible client builds still incomplete.
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The project README on GitHub describes SimpleX as a messaging platform with no user identifiers of any kind; the same README states that reproducible client builds are still an aim rather than a delivered property.
Privacy Guides lists SimpleX Chat on its Real-Time Communication recommendations page alongside Signal, Molly and Briar, describing it as a messenger that does not depend on unique identifiers such as phone numbers or usernames.
SimpleX's Privacy Policy and Conditions of Use (updated April 18, 2026) state that the SimpleX messaging protocol has no user profile IDs of any kind — not even random numbers, cryptographic keys or hashes — that servers do not create, store or identify user chat profiles, and that profiles and message history are stored only on the user's device. The same document discloses residual server-side data: the SimpleX-operated iOS notification server stores device push tokens and can observe how many queues have notifications enabled, preset servers may temporarily store IP addresses and transport data to prevent abuse, and undelivered end-to-end encrypted messages are held on preset relays until delivered or for 21 days.
UK Companies House lists SimpleX Chat Ltd (company number 13691484, registered office 20-22 Wenlock Road, London N1 7GU) with one active person with significant control, Evgeny Poberezkin, notified October 20, 2021, whose nature of control is ownership of 75% or more of shares.
The SimpleX Chat repository publishes its source code under the GNU Affero General Public License version 3 (AGPLv3), which also requires anyone operating modified server software to publish their changes.
In a post dated April 22, 2023 SimpleX's founder explains that the project is run by a commercial company rather than a nonprofit, that early support came from Wagestream founders Portman Wills and Peter Briffett and other angels, that a pre-seed round from VC fund Village Global was raised in July 2022, and that investors provided approximately USD 370,000 in total for a small share of the company, with over USD 25,000 in user donations.
In a post dated August 14, 2024 SimpleX announced a USD 1.3 million pre-seed round led by Jack Dorsey with participation from Asymmetric Capital Partners, stating that, like the Village Global investment, it is a financial investment without control or board-seat provisions, and that work with lawyer Heather Meeker had begun on an open-source governance model.
In a post dated April 30, 2026 SimpleX stated it would launch a SimpleX Network Consortium 'within a few months' — an agreement between a new SimpleX Network Foundation and the company to govern protocols and licensing — and that the Foundation's board was still being formed; as of that post, protocol governance remained with SimpleX Chat Ltd.
In a post dated November 25, 2024 SimpleX announced preset relay servers operated by Flux, a third-party decentralized cloud provider, acknowledging that before v6.2 all preset servers were operated by SimpleX Chat Ltd itself and that connection privacy therefore depended on the company honouring its policy; the Flux servers are opt-in and covered by the same privacy policy and conditions.
SimpleX's Conditions of Use state that preset server operators do not and will not sell or otherwise monetize user data, and that a future business model would charge for optional software features instead. The Privacy Policy separately discloses the sharing surfaces that remain: disclosure to meet applicable law or enforceable governmental requests, third-party hosting and network providers who may store IP addresses and transport information in their logs, and a third-party email provider for support requests.
Trail of Bits' own public publications index lists a SimpleX Chat security review dated October 2022 with a linked PDF report (reviews/SimpleXChat.pdf), independently corroborating the operator's audit announcement.
The GitHub security advisories page for the simplex-chat repository shows no published security advisories; no breach or CVE affecting SimpleX Chat was found in this research.
SimpleX's Security Policy page publishes a coordinated disclosure channel (PGP-encrypted email to chat@simplex.chat), a threat model, severity definitions, and states a further implementation security assessment is scheduled for June 2026; the page describes no bug bounty or payments.
SimpleX's post of November 8, 2022 reports that Trail of Bits, a US security consultancy, had two engineers review the simplexmq library (responsible for all cryptography and networking) for one calendar week in October 2022, finding 2 medium and 2 low severity issues — including an X3DH key-derivation implementation mistake — of which 3 were fixed in v4.2.
SimpleX's post of October 14, 2024 reports that Trail of Bits reviewed the cryptographic design of the SimpleX protocols (SMP, XFTP, XRCP, push notifications) over one week in July 2024, found no critical issues, and made recommendations (including a medium-severity finding about correlation under a compromised transport) that led to an additional transport encryption layer in SMP and other improvements in v6.1.
SimpleX's Transparency Reports page (updated February 9, 2026) states that in 2025 the company received 12 requests from law enforcement in different countries and identified or provided no responsive information, and that in 2024 it answered agency enquiries about its procedures by noting it operates under UK law.
The App Store listing for SimpleX Chat, sold by SimpleX Chat Ltd, carries the developer-declared privacy label 'Data Not Collected'; Apple notes this information is not verified by Apple.
SimpleX's Conditions of Use state that client applications should not include any tracking or analytics code and do not share tracking information with SimpleX Chat Ltd, preset server operators or any third party, and invite users to report any such code for removal.