Tessera

Closed alpha · Windows

Notes and infinite boards that stay on your disk.

Tessera is a desktop application for writing and for thinking on a canvas. Every page is a file in a folder you own. It works with no account, no network and no server. When you do want other people in a document, sharing is one sign-in away — on our servers, or on one you run yourself.

Closed alpha. Invites go out in small batches — ask for one and you will be sent an installer.

Genuinely read, and it decides who gets an invite first — the alpha is more useful with people whose work the app is likely to break.

Current build 0.0.6, Windows 10/11 64-bit. You can ask to be removed at any time.

Two kinds of page

A document editor and a canvas, in one tree.

Pages nest in a sidebar. A page is either a document or a board, and the two link to each other, so the outline and the diagram are not in different applications.

Block documents

Twelve block types — text, headings, to-dos, toggles, callouts, quotes, code with syntax highlighting, tables, images, video, columns and dividers — edited as blocks rather than as one long field, with markdown shortcuts as you type.

Databases sit inside a page as table, board, list or gallery, with filters and sorts. Mentions link pages together and backlinks show what points at the page you are reading.

Infinite boards

A GPU-rendered canvas with ten shape types drawn as signed distance fields, connectors that stay attached, frames, freehand ink, sticky comments with threads and reactions, a minimap, and a presentation mode that walks frames in order.

Mind-map mode lays a tree out for you and keeps it laid out while you add to it.

In and out

Import from Markdown, CSV and plain text. Export a page or a subtree to Markdown, HTML, PDF, PNG or SVG.

Both kinds of page keep a version history built from deltas rather than snapshots, so stepping back through a day's work is cheap.

Yours to rearrange

Every keyboard shortcut is rebindable. Light and dark themes, an accent colour, a UI scale, and a reduce-motion setting that genuinely stops the animations.

Where the work lives

On your disk, in a format you can read.

Each page is one .tnote file — JSON, in a folder under your user profile. You can copy that folder to a backup drive, put it in a git repository, or read it with any text editor. Nothing is required to be running for your notes to open.

Writes go through an atomic save, so a crash or a power cut during a save leaves either the old file or the new one, never half of each.

What Tessera sends anywhere

With no server configured: nothing. There is no telemetry, no usage reporting, no update check and no licence call. The application makes no network connection at all until you give it a server address.

That is a statement about this version, and it is testable — watch it with a firewall.

Collaboration

Sharing is a server, and you choose whose.

Tessera works with no account at all — that is the default and it stays the default. When you do want other people in a document, you sign in to a server. We run servers so that most people never have to think about it, and the protocol is published so that you can run your own instead without anything about the app changing.

Use ours

Create an account and share a page. We operate the servers, keep them patched and back them up, and there is nothing to install or maintain. Accounts, documents and uploaded media live there.

Or run your own

The same protocol, on hardware you control. The reference server is a Go program and a Postgres database, started with one docker compose up. The app cannot tell the difference, and nothing is disabled when you choose this — it is a supported path, not an escape hatch.

Conflicts are prevented, not merged

Before a gesture writes to something, the client takes a lock on it. There is no operational transform and no CRDT, because there is no concurrent write left to reconcile — and no merge algorithm that can quietly produce a shape nobody drew.

What a server can see

Whichever you pick, the server stores what is published to it in a form it can read. Documents are not end-to-end encrypted. When the server is ours, that means an administrator is technically able to read them; access is limited to what operating the service requires, but the guarantee is organisational rather than cryptographic.

That is stated in the protocol rather than glossed over, and it is why running your own remains a first-class option. How sharing and servers work →

Before you download

What this build is and is not.

Tessera is at version 0.0.7 and in early access. The feature surface is finished; the shell around it is still being built. It seems more useful to list that here than to let you discover it.

ReadyNot yet
Windows 10 and 11, 64-bit No macOS or Linux build has been made
Per-user install, no administrator prompt The installer is not code-signed, so Windows SmartScreen will warn on first run
Local editing, export and version history No automatic updates — new builds are emailed to alpha participants
Real-time collaboration against a conforming server No crash reporting, so a crash is only known about if you say so
Your notes are plain files you can copy No one-click workspace archive yet; backing up means copying the folder
Full keyboard navigation No screen-reader support — assistive technology sees nothing useful yet