SimpleX Chat: messaging without an account, phone number, or identity
SimpleX Chat is the only messaging app where the servers literally cannot know who is communicating with whom. No phone number, no username, no account — just a link.
SimpleX Chat: messaging without an account, phone number, or identity
Signal is better than WhatsApp. That’s true. But Signal has one blind spot: you need a phone number to register, and that number is tied to your identity.
Signal now hides your number from other users. But the number itself remains the key Signal uses to know who you are. If Signal receives a legal demand, they know your registration number, when you last connected, and from which IP address.
SimpleX approaches this differently. Not by hiding your number — but by not requiring any identifier at all.
No account, no identifier
This is the fundamental difference.
Every messaging app you’ve ever used — WhatsApp, Signal, Telegram, iMessage, Matrix — links your messages to an identifier. A phone number, a username, an email address, an account ID. That identifier exists on a server somewhere. That’s where someone can find you, request your data, or subpoena records.
SimpleX works differently. There is no identifier. No account. No registration.
Instead, SimpleX uses message queues: temporary addresses you create and share. When someone wants to message you, they post to your queue. You read from the queue. The server only sees: “someone placed something in this queue” — not who the sender is, not who the receiver is, and not what the message contains.
Even SimpleX’s servers cannot reconstruct who is communicating with whom. Not legally compelled, not hacked — it’s technically impossible, because the connection does not exist as a data point.
How the encryption works
SimpleX uses the Signal Protocol for end-to-end encryption of message content — the same protocol as Signal and WhatsApp. Each conversation has unique keys. Messages are encrypted on your device and decrypted only on the recipient’s device.
On top of that, SimpleX adds post-quantum encryption (CRYSTALS-Kyber) in newer versions. This protects messages against future quantum computers that could break current encryption.
The relay servers that forward messages see only encrypted packets. They don’t know the sender, they don’t know the recipient, and they cannot read the content.
What this protects compared to Signal
| Signal | SimpleX | |
|---|---|---|
| Message content | Encrypted | Encrypted |
| Phone number required | Yes | No |
| Servers know your identity | Yes (number) | No |
| Servers see who talks to whom | No (Sealed Sender) | No |
| Legally compellable data | Number + last connection | Nothing — no identifier exists |
| Post-quantum encryption | No | Yes (newer versions) |
Signal’s Sealed Sender hides the sender of individual messages, but Signal still knows your registration number. SimpleX knows nothing at all — there’s nothing to request.
Installing and getting started
SimpleX is available for Android, iOS, and desktop (Linux, macOS, Windows).
Android: via Google Play, the SimpleX website, or F-Droid (recommended on GrapheneOS).
iOS: via the App Store.
Desktop: download from simplex.chat.
On first launch, no registration is required. You choose a display name (stored locally, not shared) and the app is ready.
Making contact
There is no search function. You cannot find anyone by name or phone number — because that identifier doesn’t exist.
Contact is made via an invitation link or QR code. You generate a link, share it, the other person clicks it. That establishes the connection.
Go to New conversation → Create invitation link. Share the link via any channel — Signal, email, in person. Once used, the link is consumed.
You can also create a SimpleX address: a reusable link you can share publicly (on a website, contact page, or business card). New connections via this address require your approval before they can message you.
What you can do with it
SimpleX has the basic functionality you’d expect:
- Personal conversations (1 on 1)
- Group conversations (up to 8,000 members)
- Voice and video calls
- File sharing
- Disappearing messages (configurable per conversation)
- Incognito mode: each new contact sees a different random name
Voice messages, emoji reactions, and read receipts are present. It’s not a minimal app — it works.
Who SimpleX is for
Direct value:
- Journalists and activists protecting sources
- Whistleblowers contacting a newsroom or organisation
- People in countries with aggressive surveillance
- IT professionals reaching clients without sharing a personal number
- Anyone who wants contact without the other party needing to know their phone number
Less suitable for:
- People who want to find contacts easily (no phone book integration)
- Large groups already on Signal (switching threshold)
- People already satisfied with Signal for their threat profile
Honest caveats
SimpleX is younger than Signal. The app has existed since 2022 and is still actively developing. The codebase has been audited, but has fewer years of large-scale use behind it than Signal.
The absence of an identifier is also a usability issue: if someone sets up a new device and loses their SimpleX link, the connection is gone. There’s no “forgot password” — there’s no account to recover.
Self-hosting relay servers is possible but requires technical knowledge. For most users, the default SimpleX servers work fine.
SimpleX and Signal side by side
You don’t have to choose. Both apps serve different situations.
Signal is excellent for daily use: fast, widely supported, low barrier. If your contacts already use Signal, that’s the logical choice for most conversations.
SimpleX is the option when it matters that someone never learns your phone number or account ID — and when you want even the infrastructure that forwarded your messages to have nothing to say about who you are.
See also:
- Session guide — also without phone number, with onion routing
- Threema guide — paid, Swiss, no phone number
- Briar guide — P2P via Tor, works without internet
- Delta Chat guide — encrypted messaging over email
- Signal and Molly review — Signal with extra privacy options
- WhatsApp and privacy: what the lock does and doesn’t protect