Filarr is on Android: how it works, and what comes next

It has been the number one request since launch, and it is here: Filarr is available on Android.

The full address, if you want to share it: https://play.google.com/store/apps/details?id=fr.belouar.filarr

The version live today is 1.7.1. In our August update, we announced a release “within one to two months” and promised not to ship something unstable. We took the time: the app went through several weeks of closed testing before reaching production.

One thing up front, so you do not go looking for it: there is no iPhone version for now, and we are not announcing a date. We would rather ship one very good Android app than two average ones.

Three ways to start

On first launch, after “Welcome to Filarr!” and the language choice, the app asks one question: “How do you want to use Filarr?”. Three possible answers.

“Local only”: no account, on the phone

No account, no email address, nothing sent to a server. You set up a profile (a name, a colour, and a six-digit PIN if you want one), you pick your starter folders (Personal, Student, Professional or Creative), then you set your encryption password.

Read the “Security & encryption” screen carefully: that password is the key to your files. Filarr encrypts everything with a key derived from it, using AES-256-GCM. If you lose it, nobody can recover your files, not even us. The PIN is only a shortcut to unlock; the password always works.

“With cloud sync”: an account to find your files everywhere

You create an account (or sign in to an existing one), verify your email address, and the phone syncs your vault with your other devices. If the account already has vaults, the “Choose a vault” screen lets you open the one you want on this phone.

What goes to our servers is encrypted before it leaves the phone. The server stores opaque blocks; it reads neither your files, nor your notes, nor their titles. It is the same principle as on the computer, explained in detail in our post on zero-knowledge sync.

“Already using Filarr elsewhere?”: pairing

This is the most interesting path, and the one we recommend if Filarr already runs on your computer.

Pairing: your key moves from one device to another, not through us

Your vault is encrypted with a key. For the phone to read what the computer wrote, it needs the same key. The question is: how do you hand it over without anyone else seeing it on the way?

In practice:

On the computer (or in the web app): Settings › Account & Sync › Connected devices › Manage › Pair a new device. A six-digit code appears, with a QR code.
On the phone: at the “Receive your vault key” step, type the code or scan the QR code.
Compare the verification number both devices show. If they match, confirm.

What happens meanwhile? The two devices perform an ECDH key exchange on the P-256 curve: each sends a public key, and each derives, on its own side, a shared secret the server never sees. Your vault key then travels encrypted under that secret. Our server only passes the messages along; it sees bytes it cannot open.

The verification number has one precise job: making sure nobody slipped in between your two devices. If someone intercepted the exchange to impersonate one of them, the two numbers would differ and pairing would stop. That is why you really should compare them, especially if you typed the code by hand.

The result: the phone receives the key the computer already uses. Nothing needs to be re-encrypted, and your files stay readable everywhere. If pairing is not possible (no other device at hand, for instance), “Use my account password instead” is still there.

To pair a second phone from a first one: Settings · Sync · Pair new device.

What the phone does

The app is not a viewer: it is Filarr, complete or nearly so, in your pocket.

Your files. Folders, favourites, tags, and a search inside document contents (PDF, Word, spreadsheets, text), with an encrypted index that stays on the device. Previews open without leaving the app. You decide what takes up space on the phone: a file downloads when you open it, or stays available offline if you pin it.

Your notes. The same editor as on the computer: headings, lists, tasks, tables, callouts, formulas, links between notes, notebooks, reminders. Built-in databases are there too, with the desktop's column types (relations, formulas, rollups…), along with the graph of your notes.

Your tasks. The Tasks tab follows your tasks' due dates like the desktop does, and shows who each one is assigned to.

Working with others. Shared vaults open on the phone: you can drop files into them, edit a note live with the other members, and comment. The inbox gathers the mentions, replies and tasks that concern you.

Sending and receiving. Filarr Send sends one or several files through an encrypted link whose key lives in the link and never on our server. File requests let you receive encrypted uploads from people who have no account.

What does not leave the phone

Your content, encrypted with AES-256-GCM on the device before any sync.
Your photos, except the ones you pick. Version 1.7.1 removed the photo and video access permissions: importing goes through Android's picker, which only gives the app what you hand it.
Usage statistics, unless you turn them on. At the end of setup, the “Share anonymous usage statistics” switch is off by default. If you turn it on, it never sends the contents of your vault.

What is not there yet

We would rather tell you here than let you find out:

iPhone and iPad: no app, and no date announced.
Imports from Obsidian, Notion or Evernote happen on the computer, not on the phone.
Passkeys are not available on mobile yet.
No push notifications for mentions: the inbox updates on sync and when you come back to the app.
Tasks from a shared-vault note can be read in the Tasks tab but not edited there yet: you need to open the note.
The latest database features (database templates, automatic dates, Merise-style schema, SQL queries) stay on the computer and the web for now.
Plugins only run on the computer.

What comes next

The next Android version is already written. It is not released yet, but it includes in particular:

two-factor authentication set up right on the phone when an organisation requires it (before, you had to go through the computer);
a confirmation before emptying a shared-vault note entirely, as on the computer;
a safeguard for shared-vault notes too heavy for live editing, which no longer lose changes;
the display of the permanent drop boxes from the bookkeeping gateway and the status of each deposit;
a corrected pairing path on screen: the “Receive your vault key” step in 1.7.1 points to a menu that does not exist on the computer. The right path is the one given above.

After that, with no date: faster large databases (the same engine as the desktop), and above all continued parity with the computer. Every feature that lands on the desktop is inventoried on the mobile side, and we publish what is missing rather than keep quiet about it. What arrives on the desktop in the coming weeks is detailed in the Filarr 3.6 post, and the full roadmap is on the roadmap page.

Try it

Android: Filarr on Google Play
Windows, macOS, Linux: the download page
Browser: app.filarr.com

If something does not work as described here, tell us from the app (Settings › Help and feedback) or through the contact page. And if you like the app, a rating on Google Play helps an independent project get found more than you might think.