Download

Speed meets privacy.

A chat app for messages, groups and calls.

Post-quantum encryption: ML-KEM-768, the NIST standard (FIPS 203), on the open MLS protocol. A personal AI assistant inside. On your phone and your computer.

Get faast.chat

Free. Your phone number is your account.

For this device

Android

Download the APK and open it to install. Android may ask you to allow installs from your browser first.

Download
For this device

iPhone

The iPhone app is in beta on TestFlight. It is by invitation for now.

Invitation only
For this device

Windows

A native app written in Rust, for Windows 10 and 11, 64-bit. It isn't signed yet, so SmartScreen will ask you to confirm.

Download
For this device

Mac

A native app written in Rust, for Macs with Apple silicon (M1 or later), macOS 11 or later. Signed and notarized by Apple. It updates itself.

Download
For this device

Linux

A native app written in Rust, for 64-bit Debian 12 and Ubuntu 22.04 or later. The .deb package adds our signed APT repository, so faast updates with the rest of the system.

Download

Next to the apps you know

Only rows we can defend, from each service's public documentation.

FeaturefaastWhatsAppTelegramSignal
End-to-end encryption by default, in every chatTelegram: only in secret chats you open on purpose Yes Yes No Yes
Open IETF standard protocolMLS, RFC 9420 Yes No No No
Post-quantum key exchange Yes Not documented No Yes
Real-time typing Yes No No No
AI assistant in the chat, with your choice of model Yes One model Through bots No
Personal compute space with scheduled scripts Yes No No No
Native Windows appWritten in Rust. Not Electron, not a web page in a window Yes No Yes No
Native Mac appSignal's is Electron Yes Yes Yes No
Native Linux appWhatsApp has none; Signal's is Electron Yes No Yes No
Tor built inProxy settings are not the same thing Yes No No No
Address book not stored on the server Yes No No Yes
An API to send yourself notifications Yes Business, paid Bot API No

As of October 2026, based on each service's public documentation. Spotted something out of date? Tell us and we will fix it.

What makes faast different

Six ideas built into one app. Nothing to install on top, no second account.

They read it while you write it

Your words show up on the other screen as you type, letter by letter. It's on by default, and one tap on ⚡ turns it off for any chat. Live drafts are end-to-end encrypted, like every message.

Encrypted on an open standard

Every chat uses MLS, the IETF standard for end-to-end encryption, through the open-source OpenMLS library. One protocol for 1:1 chats and for groups.

Post-quantum: chats use ML-KEM-768, the NIST post-quantum standard, so what is sent today stays closed even to a future quantum computer.

Protocol
MLS, RFC 9420
Suite
MLS_128_DHKEMX25519_AES128GCM_SHA256_Ed25519
Files, voice
AES-256-GCM

Dana, your assistant, in the chat

Write to her like a contact. She answers, sums up a chat for the period you pick, and reads the web if you allow it. She sets reminders and runs actions on a schedule.

You choose her brains, the AI models, and their order. Every answer written by a model says which one wrote it.

  • Weather
  • Recipes
  • Currency
  • Places
  • Holidays
  • Wikipedia
  • YouTube
  • Reminders

Your own miniserver

Every account gets a private compute space. Ask Dana for a small script, like “tell me when this channel posts a video” or “a news digest every morning”, and it runs on a schedule. Results arrive as messages.

Each run gets its own throwaway micro-VM. Files, folders and Run now are right in the app.

youtube_watch.pyevery hour
news_digest.pyevery day at 7:30

Every device is a full member

Android, iPhone and Windows, each with its own keys. Your computer keeps working when your phone is off. Up to four accounts on one phone.

Tor, built in

Hide your IP address and where you connect from, even from us. In the Android, iPhone and Windows apps, with nothing to install.

This site in Tor Browser: http://a5jxnlwb7bt3ddbjgfonz6pdoy6z5emelaslk5tzmhrzxjpvagckyzyd.onion

Everything you expect, done well

  • Chats and groupsSame encryption for both.
  • Voice and video callsOne to one, with CallKit on iPhone.
  • Photos and videosEncrypted before they leave.
  • FilesDocuments and PDFs.
  • Voice messagesHold, talk, send.
  • Live locationShare where you are as you move.
  • ReactionsAny emoji.
  • Replies and quotesAnswer the exact message.
  • Rich textBold, italic, spoiler, monospace and more.
  • DraftsUnsent text waits in each chat.
  • Themes and wallpapersA different look for every chat.
  • Who is typingIn groups too.
  • Online ringA ring around whoever is online.
  • Games in chatConnect 4, tic-tac-toe, draughts, chess and go.
  • Forward and searchFind any message again.
  • Archive and muteQuiet chats stay out of the way.
  • Several accountsUp to four on one phone.
  • 13 languagesArabic and Urdu right to left.
  • TrilloThe bell that makes the other phone ring, like the nudge of the old days. At most twice a minute, and never in a muted chat.

Privacy, said plainly

What we protect, and what we would rather tell you now than have you find out later.

What we protect

  • Your messages are end-to-end encrypted, always.Nobody else can read them. Not even us.
  • Your address book is matched in memory and never stored.
  • Notification content never passes through third parties.Your phone gets a wake-up. The message is downloaded and decrypted on the device.
  • Photos, files, voice messages and live drafts are encrypted too.
  • Sealed messages leave our server once they are delivered.After 30 days at most, delivered or not.

What we tell you openly

  • Backups are on by default. A password makes them yours alone.Without one, we hold the key, so an SMS code can bring your history back on a new phone. With a password, only you can open it, and if you lose it the history is gone. We suggest one. We don't force it.
  • Dana reads what you write to her.Any assistant has to. She can't see your other chats, except one you ask her to sum up. Her built-in brain runs on our own server in Europe. If you add your own AI key, those texts go to that provider.
  • Our servers see metadata.Who writes to whom, when, and how much. Never what you wrote.
  • Tor hides where you connect from. It does not make you anonymous.Your account is your phone number.
  • Profile photos are visible to your contacts.Like on any messenger.

Send yourself notifications from anything

Anything that can make an HTTPS call can write to you: a script, a server, a smart home, a monitoring tool. Dana brings the message to your chat or to a group, end-to-end encrypted like any other. Make a token in the app under Assistant › API › New token.

  • “Your website is down”Uptime Kuma writes to you through faast, set up as an ntfy or Gotify notification.
  • “Someone is at the door”The camera's snapshot comes along as a photo, up to 10 MB.
  • “The washing machine is done”Sent to the family group with Dana in it, so everyone at home sees it.
  • “Build 214 passed”One line at the end of your pipeline, or the step that failed.
  • “Disk 92% full”Alerts from Proxmox, Grafana or Synology DSM, pointed at faast without writing code.
  • “The nightly backup didn't run”Your job checks in every night. When it stops, Dana notices the silence and tells you.
  • “Upload: 64%”A long job keeps updating the same message, so the chat stays one line.
  • “Greenhouse at 4 °C”A sensor on a Raspberry Pi and a few lines of Python.
  • Files and photos up to 10 MB, uploaded or fetched from a link.
  • One bubble that updates: edit or delete the same message, so a progress bar stays one line.
  • “Tell me if it goes quiet”: your job pings faast, and Dana writes to you when the ping stops.
  • Works with ntfy, Gotify and Pushover: point the tools you already use at faast, no code to change.
$ curl -sS https://msg.faast.chat/api/v1/notify \
    -H "Authorization: Bearer $FAAST_TOKEN" \
    -H "Content-Type: application/json" \
    -d '{"title":"NAS","text":"Backup done: 3.1 GB"}'
{"ok":true,"id":"…"}
Read the API manual (PDF)

Questions

Is it free?

Yes. There is nothing to pay today. Dana's built-in brain has a fair-use limit per hour and per day. Add your own AI key and that limit does not apply.

Who can read my messages?

Only the people in the chat. Messages are end-to-end encrypted with MLS and decrypted on their devices. Our servers pass along sealed envelopes: they see who writes to whom and when, never the content. A chat with Dana is different, because she has to read what you send her.

What is post-quantum, and does faast have it?

A large quantum computer could one day break today's key exchange, and traffic recorded now could be opened then. Post-quantum key exchange closes that door. faast has it: chats use ML-KEM-768, the NIST post-quantum standard (FIPS 203), with AES-256-GCM. Channels and the chat with yourself move to it next.

What is Dana, and where does she run?

Dana is an assistant you chat with like a contact. She runs on our servers. Her built-in brain is an open model on our own machine in Europe. You can add other brains, such as OpenAI, Anthropic, Gemini, Groq or OpenRouter, with your own key. Then the texts you give her go to that provider.

What happens if I lose my phone?

Your other devices keep working, because each one is a full member of your chats. On a new phone, sign in with your number. If your backup has no password, an SMS code brings your history back. If it has one, you need the password: without it, nobody can open that history, us included.

Why a phone number?

It is how your friends already find you, so there is no new username to hand out. Your address book is checked against faast in memory and never stored.

What does Tor do, and what doesn't it do?

Tor hides your IP address and where you connect from, from your network and from us. Your traffic stays inside Tor all the way to our onion service. It does not make you anonymous: your account is still your phone number. Calls do not go through Tor.

Which languages?

The app speaks 13: English, Italian, Spanish, French, German, Portuguese, Russian, Chinese, Japanese, Arabic, Hindi, Bengali and Urdu.