SimpleX Chat is a private, open-source instant messenger that assigns no user identifiers at all — no phone number, username, or account ID. Contacts connect through one-time links or temporary addresses, and messages are end-to-end encrypted.
SimpleX Chat is an open-source messaging app that removes user identifiers from the equation entirely: there is no phone number, no username, and no permanent account ID to hand over. Instead, you create a one-time invitation link or QR code, and the person you want to reach uses it to open a private connection. Every chat then runs through paired one-way message queues on relay servers, so no server sees both sides of a conversation. Contacts, groups, and message history are stored only on your device, and you can move that encrypted data to another device when you switch. It fits anyone who needs private, practical day-to-day communication without building a public social graph along the way.
Under the hood, SimpleX Chat separates sending from receiving. Each contact relationship uses its own pair of queues hosted on different relays, and the servers hold anonymous credentials rather than identities, so they cannot map who talks to whom. File transfers travel over a separate protocol designed to limit metadata leaks, and voice notes, images, and documents stay end-to-end encrypted. Groups work the same way: membership lives on participants' devices, and outsiders have no way to discover that a group exists. Calls, including video, are encrypted too, and optional Tor routing hides your IP address from relays. If you also want tighter control over what starts with Windows, our Autoruns guide covers that side of privacy housekeeping.
The main benefit of SimpleX Chat is that privacy is structural rather than a setting you remember to switch on. Because nothing ties your conversations to a name, phone number, or reusable address, there is no profile directory to scrape and no social graph for a server operator, advertiser, or attacker to reconstruct. Spam becomes largely impossible, since nobody can message you without an invitation you chose to share. You keep custody of your own data: profiles, contacts, and history stay on your device, and the encrypted database can move with you. Connections survive in a decentralized network where anyone can run a relay, and encrypted delivery works while your phone is offline. Practical features matter too — disappearing messages, incognito profiles that generate a fresh random name per connection, secret groups, voice notes, and encrypted audio and video calls. The result is secure messaging that still behaves like a normal chat app day to day.
There is no sign-up form, phone number, or username to create. You connect by sharing a one-time invitation link or QR code that contains only public keys and works once, or by publishing a temporary SimpleX address if you want to be reachable more widely.
Each connection uses two separate unidirectional queues hosted on different relays, one for sending and one for receiving. Servers hold anonymous credentials instead of identities and never see both halves of a conversation, so they cannot build a map of who is talking to whom.
Messages, calls, and files are end-to-end encrypted with continuous post-quantum hybrid key exchange, forward secrecy, and break-in recovery. Content is padded to a fixed size before every encryption layer, which hides message length from observers, and security codes let you verify a contact's keys out of band.
Groups are decentralized: membership lists live on participants' devices rather than on a server, and no one outside the group can discover that it exists. Invitations are explicit, member roles control who can post or invite, and group messages remain end-to-end encrypted throughout.
Chat profiles let you present different names and images to different audiences. Incognito mode goes further and hides your chosen profile from new contacts entirely, generating a fresh random display name for every connection you make or group you join.
Set messages to vanish automatically after a chosen interval, edit or delete what you sent, reply to specific messages, and react with emoji. SimpleX Chat deliberately omits read receipts, because they pressure recipients and keep senders waiting on a screen.
Voice notes, audio calls, and video calls all stay end-to-end encrypted between participants. Calls are placed between contacts you already trust, so no server can eavesdrop on the conversation, and you can ignore a ringing call without revealing anything about your availability.
Images, videos, and documents travel through a separate file-transfer protocol designed to reduce metadata leaks. Your profiles, contacts, and history live in an encrypted local database that you can move to another device, and a terminal client plus bot API support scripting.
No. SimpleX Chat has no user identifiers at all — no phone number, email address, username, or randomly generated account ID. You create a local profile on your own device, and there is nothing to register, verify, or recover through a central service.
You share a one-time invitation link or QR code with the person you want to talk to, or publish a SimpleX address if you want to be reachable by more people. Both can be sent through any channel you trust, and you approve each new connection before it is completed.
Most messengers, even encrypted ones, tie you to a phone number, username, or global key. SimpleX Chat has none, and it routes each conversation through two separate one-way queues on different servers, so relay operators cannot see who is talking to whom or assemble a social graph.
Relays handle anonymous credentials rather than identities and see only encrypted traffic that resembles random noise. They do not store your profile, contacts, or delivered history, they cannot observe the full connection graph, and they keep a message only while your device is offline.
Yes. The desktop app can connect to your existing mobile profile by scanning a QR code or using a connection link, so both stay in step. Because your data lives on your device, you can also move an encrypted copy of your chats to another machine when you switch.
Not by itself — messages travel through relay servers, and those servers can see your network address. You can route SimpleX Chat through Tor to hide your IP address from relays, which also makes it harder to correlate your separate connections with each other.
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