Tasfer

Tasfer is an open-source Markdown editor that draws the document directly on HTML5 Canvas while keeping the user's writing on their own device. It combines a structured block model with the formatting expected from a rich text editor, so it isn't limited to typing raw Markdown into a plain text box. The local-first design removes the need for a cloud account and keeps the editor available offline. People can open the web app without installing anything, use an app build, or inspect the source. The product is aimed at writers who want capable document editing without making hosted storage the price of convenience.

The editor organizes content into blocks such as paragraphs, headings, bullet lists, numbered lists, to-do lists, images, and dividers. Within those blocks it supports bold, italic, strikethrough, inline code, and links. Mathematical writing gets a Canvas-native LaTeX renderer rather than a separate embedded document surface. Tasfer also documents bidirectional text support for Arabic, Hebrew, and other right-to-left languages, along with a user interface that can be internationalized. Because text and math are painted onto Canvas instead of ordinary document elements, the project controls layout, input, and rendering consistently across the environments it supports.

That rendering system is also available as a developer component. The headless and framework-agnostic @tasfer/editor package contains the document model, schema, actions, CRDT, and Canvas renderer. A separate @tasfer/react package supplies React 19 bindings with a hook and editor component. Both engine packages use the MIT license, while the full Tasfer application uses AGPL-3.0. Developers can embed the editor core in another product and provide their own nodes, formatting marks, theme, and sync providers. This makes Tasfer relevant both as a ready writing app and as an editor toolkit for teams that don't want to build Canvas text behavior and collaborative merging from scratch.

Documents stay local, with SQLite-backed storage adapted to each runtime. The operation log is the source of truth, and snapshots plus lazily synced, content-addressed assets support the working document. Collaboration uses an operation-log CRDT, which stamps changes with logical time and merges character-level edits from different peers so offline work converges after reconnection. Peers exchange their current versions and send the missing operations, then stream new changes in real time. This is a practical distinction from simple file transfer because two people can continue editing and let the document model reconcile their operations rather than choosing one complete copy over another.

Sync remains optional and peer to peer. Devices discover one another through a stateless signaling relay, establish direct WebRTC data channels, catch up on missing operations, and then exchange new work. Each device creates its own Ed25519 key pair, and one-time pairing invitations establish trust through mutual signature verification. Peer communication is end-to-end encrypted, so collaborators hold the keys needed to read the material. If a direct path can't be established, relay-forwarded transport is available as a fallback, and the project says the relay can't decrypt the notes or retain an account and message history. Users can also configure their own relay.

Tasfer has paths for the web as a progressive web app, macOS, Windows, and Linux through Electron, plus iOS and Android through Capacitor. The same core handles keyboard, mouse, touch, and input method editor behavior, while each platform supplies its own storage and runtime layer. That breadth suits people who switch between a desktop and phone, writers who need offline access, technical authors using code and LaTeX, and small groups that want direct collaboration. The browser route offers the lowest-friction way to try it, while the repository includes desktop and mobile projects for users and contributors working across those environments.

The main tradeoff is maturity. Tasfer's homepage calls the product a public beta and says it runs and syncs but will break, with no guarantee that writing will survive an update. Important documents still need independent backups, and self-hosting a relay or embedding the editor core requires technical setup. There is no account, advertising, analytics, subscription, or paid storage tier shown, so open source is the clearest pricing posture. The app can be audited, forked, and run under AGPL-3.0, while the reusable editor and React packages are MIT-licensed. Tasfer already has a substantial editor architecture, but buyers should treat its beta warning as seriously as its privacy promises.