SimpleX vs Session: Which Private Messenger Should You Use?

SimpleX Chat and Session are the two messengers for people who want privacy beyond encryption. Both skip phone numbers. Both hide metadata. Both are free and open source. The difference is in how they hide you — and that difference shapes everything about using them.

Most comparisons call one of them "the winner" without explaining the trade-off. This guide compares them the way you will actually use them: signing up, adding contacts, calling, and what each one cannot do — with facts checked against the current Play Store listings.

Quick comparison

Play links: SimpleX Chat on Google Play · Session on Google Play

The core difference: no ID vs a random ID

Every messenger has to know where to deliver your messages. Most use a phone number or username. Session uses a random 66-character ID generated when you open the app — no phone, no email. That ID reveals nothing about who you really are, but it is persistent: the same ID across every conversation, so in theory your contacts (or anyone watching the network) can see that the same ID talks to the same people over time.

SimpleX goes one step further: it has no user ID at all. Not a phone number, not a username, not even a random number. Instead, each conversation gets its own temporary, anonymous address — a kind of disposable mailbox that exists only between you and that one contact. The relay servers that carry your messages never learn who you are, and they cannot connect your conversations with different people to each other. There is no table of users anywhere for anyone to seize or leak.

That is the strongest privacy design of any mainstream messenger. The price is convenience, which we will get to.

Signing up and adding contacts

Session works like a messenger with a strange username. Open the app, get your Session ID, and share it with anyone — post it publicly if you like, since it says nothing about your identity. People add you the way they would add a username on any chat app. Simple and familiar.

SimpleX works like exchanging secret handshakes. You create a profile (just a display name, stored only on your phone), and to talk to someone you send them a one-time invitation link or have them scan a QR code. For repeated contact you can create a long-term address that accepts requests automatically. There is no directory, no search, no way for a stranger to find you unless you hand them a link.

That is brilliant for privacy — nobody can spam you, ever — but it is real friction. Meeting someone new usually means sending the link through another channel first, and sharing a QR code during a video call is the safest way to do it, since a link sent over a compromised channel could be swapped.

Calls, groups, and everyday features

Both apps cover the basics: end-to-end encrypted messages, disappearing messages, file and photo sharing, voice notes, and group chats. Beyond that, they differ.

SimpleX has working end-to-end encrypted voice and video calls (over WebRTC), with the option to use your own relay server so even call metadata stays away from third parties. Its secret groups hide the group's very existence and membership from outsiders. Extras include an incognito mode that gives each contact a different profile, message reactions, and a portable encrypted chat database you can move to a new phone with a passphrase.

Session offers voice and video calling, but calls are still in beta and switched off by default. Closed groups support up to 100 people with the same encryption as one-to-one chats. Where Session is thinner on features, it is more polished in the basics — and its 4.68 Play rating from 37,000 reviews, versus SimpleX's 3.99 from under 3,000, reflects a more mature, battle-tested app in users' hands.

Honest limitations of each

No comparison is honest without the downsides, and both apps have real ones.

Session's limitations: its protocol currently lacks perfect forward secrecy — if someone captured your long-term key and intercepted your messages when sent, past chats could theoretically be decrypted (a V2 protocol fixing this is in development). Push notifications on Android travel through Google's servers. There is no cloud backup: lose your phone without your recovery seed phrase written down, and your history is gone. And with far fewer users than Signal, getting your contacts to join takes effort.

SimpleX's limitations: the invite-link model makes starting conversations awkward, especially with people you have never met. Your profile lives only on your device — great for privacy, but a new phone means a deliberate transfer. Delivery can be slower than centralized apps, and the app asks you to understand concepts (relays, addresses, security codes) that mainstream messengers hide. The smaller user base means fewer people to talk to and less real-world testing.

Getting started: what the first five minutes look like

If you install Session, the first run is quick. The app generates your Session ID automatically — a long string of letters and numbers plus a QR code. Write down the recovery seed phrase the app shows you and keep it somewhere safe; it is the only way back into your account if you lose your phone. Then share your ID with a friend through any channel (even an insecure one, since the ID alone reveals nothing about you) and start chatting. There is nothing to configure before your first encrypted message.

If you install SimpleX, the first run asks for a display name and then suggests setting a passcode or system lock for the app — do it, since your whole profile lives on this device. To talk to someone, tap to create an invitation: you get a one-time link or QR code to send them. The safest way to share it with someone new is during a video call or in person, because a link passed through a compromised channel could be swapped by an attacker. For people you talk to often, create a long-term address in the app so they can reach you without a fresh link each time. It takes a few minutes longer than Session, but each step is there for a reason.

Whichever you choose, verify the connection security code with important contacts (both apps show one) — it confirms nobody is sitting in the middle of your conversation.

Which one should you pick?

Pick SimpleX if: your priority is the strongest possible privacy design and you are willing to trade convenience for it. Journalists, activists, and anyone whose threat model includes network-level surveillance will appreciate that no server anywhere holds a record of who they talk to. See also our Signal vs Session comparison for how Session fits against the mainstream private option.

Pick Session if: you want serious anonymity without giving up the familiar feel of a messenger. Sharing an ID is easy, the app is mature and highly rated, and onion routing plus no phone number is already far beyond what WhatsApp or Telegram offer. Our private messenger alternatives guide has more options in this space.

Either way, both apps share one weakness worth remembering: the most private messenger in the world is useless if the person you need to reach will not install it. For most people, the realistic answer is one of these for sensitive contacts and a mainstream app for everyone else — and our Element vs Signal comparison covers the middle ground between the two worlds.

FAQs

Which is more private, SimpleX or Session?

SimpleX is more private in design because it has no user ID at all — not even a random one — so servers cannot build a map of who talks to whom. Session has a persistent random ID that reveals nothing about your real identity but can be linked across conversations.

Does SimpleX require a phone number?

No. SimpleX needs no phone number, email, username or any identifier. Your profile lives only on your device and you add contacts with one-time invitation links or QR codes.

Is Session really anonymous?

Session gives you a random 66-character Session ID with no phone number or email, and routes messages through onion routing so your IP stays hidden. It is pseudonymous — the ID cannot be tied to your real identity, but it stays the same across conversations.

Does SimpleX have voice and video calls?

Yes. SimpleX supports end-to-end encrypted audio and video calls over WebRTC, and you can optionally use your own relay server to keep call metadata away from third parties.

Which is easier to use, SimpleX or Session?

Session is easier. You share a Session ID like a username and anyone can message you. SimpleX needs a one-time link or QR code per contact, which is more private but less convenient.

Are SimpleX and Session free?

Yes. Both apps are free and open source with no ads and no paid tiers.