simplex-chat

Open source alternative to WhatsApp and Telegram

19.6K stars
AGPL-3.0
Active this week
Last commit 1 day ago

Last verified Oct 20, 2026

Secure messaging without user IDs through SimpleX private relays. AGPL-3.0 apps and servers for teams that prioritize metadata privacy.

Visit website GitHub19.6K Deploy on Hostinger

Read the full breakdownWho it is for, how it works, trade-offs and the FAQ

who it's for

Who simplex-chat is for#

Privacy-focused personal messaging

Use SimpleX Chat when hiding your contact graph matters as much as encrypting message contents.

Skip if:

You need the largest possible mainstream contact network.

Sensitive communities

Community organizers can use SimpleX when members should not expose reusable usernames or phone numbers.

Skip if:

Your group depends on public searchable identities and casual discovery.

Developer experiments on private protocols

Developers can build bots and services on the SimpleX protocol and server stack.

Skip if:

You only need a hosted team chat tool with admin dashboards and enterprise integrations.

the problem

The problem it solves#

Private messaging is not only about encrypting message bodies. Users also need protection from metadata leaks that reveal identifiers, contact graphs, and conversation relationships. SimpleX Chat addresses that problem by avoiding reusable user IDs in the network design.

how simplex-chat solves it

How it solves it#

No user IDs

SimpleX does not assign users phone numbers, usernames, account IDs, or random persistent identifiers for message delivery.

Private connection setup

Users establish contacts by sharing a link or scanning a QR code, which avoids public discovery by default.

Pairwise queue design

The README describes pairwise per-queue identifiers, so different contacts do not share one visible user identity.

End-to-end encrypted chats

SimpleX uses end-to-end encryption for conversations and describes double ratchet encryption for forward secrecy and break-in recovery.

App and server ecosystem

The repository covers iOS, Android, desktop, terminal app, server, bot, and protocol components.

strengths · trade-offs

Strengths and trade-offs#

Strengths

Metadata protection is coreSimpleX's main distinction is that it removes reusable identifiers rather than only encrypting message contents.
Open protocol directionThe README says SimpleX protocols are open and public, which supports third-party clients, servers, bots, and services.
Strong privacy comparisonThe README directly explains how SimpleX differs from Signal, Matrix, Session, Ricochet, and Cwtch for identifier privacy.

Trade-offs

-Different onboarding modelUsers must share invitation links or QR codes, which is more deliberate than searching for a phone number or username.
-Earlier-stage ecosystemThe README says SimpleX is still relatively early stage and users may find bugs or missing features.
-Default server expectationsThe README says default servers are best effort, so high-assurance groups should evaluate self-hosting or server choice.

versus alternatives

simplex-chat vs alternatives#

Compared to Signal

Signal is easier for most people to adopt because it uses phone-number-based discovery and has a much larger user base. SimpleX Chat makes a different tradeoff: it removes reusable user identifiers from the messaging design, which better protects contact metadata and social graphs. Choose Signal for mainstream encrypted messaging; choose SimpleX when identifier privacy is part of the requirement.

tech stack · detected from GitHub

What it's built on#

Languages: C++HaskellJavaScriptKotlinPythonSwiftTypeScript

frequently asked

FAQ#

What makes SimpleX Chat different?

SimpleX Chat does not assign users identifiers of any kind, not even random ones. That reduces metadata exposure across conversations.

How do users connect on SimpleX Chat?

Users share an invitation link or scan a QR code to create a private connection.

What license does SimpleX Chat use?

GitHub metadata reports SimpleX Chat as AGPL-3.0 licensed.

Does SimpleX Chat replace Signal for everyone?

No. Signal has a larger mainstream network and simpler onboarding. SimpleX is best when no-ID metadata protection is the priority.

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Hostinger

Run simplex-chat on your own server

Self-host simplex-chat on a Hostinger VPS.

Deploy on Hostinger

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Who simplex-chat is for#