Flux

One desktop queue for files, media and torrents.
Open-source Windows download manager · Rust engine · Chromium and Firefox integration

English · Türkçe
Download · What's new · Features · Installation · Validation · Development

Flux combines segmented HTTP transfers, accessible video/audio capture, native BitTorrent, a persistent local history and separate desktop approval windows. It is built with Tauri 2, React 19, Tokio and SQLite WAL. The name refers to flow: files and media moving from your browser into your download queue.

Before downloading: connect your browser. Install and enable the Flux extension, grant its requested site/native messaging permissions, and refresh open tabs. Launch Flux once: the installed and portable editions automatically register and repair the local browser bridge. If the extension still cannot connect, use Settings → Browser integration → Repair browser bridge. The desktop shows this guidance on first use; dismissing it keeps it hidden on later launches. Bridge registration does not install the extension.

Download

Current release: Flux 2.2.0, Windows x64.

Code signing policy · Privacy policy

Application update packages carry a signature checked against Flux's embedded verification key. The Windows installer and executables do not have an Authenticode publisher certificate; Windows may display a publisher or SmartScreen warning. Firefox ZIPs are unsigned and require Mozilla signing for permanent installation. See release and signing and browser distribution.

Previous 2.0.0 and 1.7.0 packages remain available.

What's new in 2.2

• Automatic browser setup: startup repairs missing or outdated local host registration for Chrome, Edge, Brave, Chromium and Firefox without a manual Settings step. A dismissible first-use reminder explains extension permissions; Settings shows registration status and offers repair.

• Media handoff repair (14 October): Chromium and Firefox wait for desktop confirmation and display transfer errors. Captured quality/output is ready in the approval window without another inspection; optional reinspection preserves the captured source, filename and output format. Empty newer fields are omitted for older native hosts. Refresh the desktop and extension packages together; this repair keeps version 2.2.0, so an existing 2.2 installation needs a manual package refresh.

• Browser handoff before file selection: Chromium cancels its held transfer before releasing the filename gate; Firefox intercepts attachment navigation at response headers. Flux opens its approval window in the foreground.

• Checkpoint resume without ETags: range support no longer requires a strong ETag. Saved prefixes are SHA-256 checked before appending; changed remote content cannot silently produce a mixed file.

• Progress retained on non-range sources: Flux verifies and discards a replayed prefix before appending new bytes. Saved disk data and progress remain; prefix replay still costs network bandwidth.

• Media-button switch: show/hide page video buttons from the extension popup, immediately in open frames. Re-enabling restores a dismissed HUD.

• Automatic languages: new desktop profiles follow the OS; extensions follow the browser UI language. Unsupported locales use English; explicit choices persist.

• Direct Settings access: open the separate Settings window from the top menu or toolbar.

Read the release notes, technical changes and validation.

Features

HTTP and disk

Workers write bounded network buffers to non-overlapping offsets in task-owned staging. Aligned Windows transfers use unbuffered positional writes; existing unaligned checkpoints retain buffered writes. Linux/macOS allocation adapters are included in source. Completion uses one integrity read and exclusive publication without a chunk-merging pass. This is positional I/O, not a kernel-level zero-copy networking claim.

Disconnects, truncated responses, rate limits and retryable server errors have bounded recovery. Global/per-task token buckets control bandwidth. Resume checks local checkpoints and source identity; validator-free sources are compared to saved prefixes. Changed validators, sizes or prefixes are handled explicitly instead of mixing different objects.

Media

The extension observes elements, frames, requests and bounded fetch/XHR manifest snapshots. Bundled yt-dlp resolves metadata asynchronously; FFmpeg/FFprobe inspect and assemble selected streams. Resolution choices are deduplicated, and selected audio belongs to the same provider item.

Finite media without an exact byte total can show size, percentage and ETA estimates marked ≈, using duration/segment metadata. Live streams or insufficient metadata remain indeterminate. Blob URLs need accessible underlying resources; DRM, CAPTCHA and login challenges are not bypassed.

Torrents

Flux embeds librqbit 9.0.1 for v1 and libtorrent 2.1.2 for v2/hybrid without a separate daemon. HTTP and torrents share bandwidth budgets. Seeding supports ratio, duration, either condition, unlimited sharing or disabled sharing. The default ratio is 1.0; global/per-task choices persist across restarts. Per-torrent speed limits accept unlimited (0) or at least 16 KiB/s.

See the 2.2 desktop

Screenshots from isolated Windows regression tests with local fixture media.

Media progress and estimated remaining time	Torrent sharing controls

Installation

Desktop

1. Run Flux_2.2.0_x64-setup.exe; installation is per-user.
2. FFmpeg, FFprobe, yt-dlp, Node and torrent runtimes are bundled. Missing WebView2 is installed using Microsoft's bootstrapper, which needs internet access.
3. Native Messaging is registered for Chrome, Edge, Brave, Chromium and Firefox. Host registration does not install a browser extension.
4. Launch Flux once after installing the extension. Both installed and portable editions register/repair the bridge automatically at startup. Settings → Browser integration → Repair browser bridge remains available if permissions or files prevent automatic registration.

Data lives under Flux in the current user's local application-data directory; downloads default to Downloads/Flux. Upgrades retain history/preferences. Back up important data before changing installations.

Upgrade from public 1.7/2.0 packages by running the 2.2 installer manually. Those older packages do not gain the new updater until 2.2 is installed.

Chromium browsers

1. Extract the Chromium extension ZIP or use the installed extension directory.
2. Open chrome://extensions or edge://extensions, enable Developer mode, select Load unpacked, and choose that directory.
3. The unpacked ID is iheejmamcoeigoallciifjminjnnnlbj. Enable interception in extension settings and check the desktop connection.
4. After updating, reload/update the extension and refresh media tabs. Extensions update separately from the desktop installer.

Firefox

Use the matching 140+ or 120–139 package. Open about:debugging#/runtime/this-firefox, select Load Temporary Add-on, and choose the extracted manifest.json. Enable local Flux data transfer in extension settings and grant site access when requested.

Temporary add-ons disappear after restarting Firefox. Standard Firefox requires a Mozilla-signed XPI for permanent installation. Store publication is separate; these ZIPs do not imply a public store listing. See Firefox setup.

Another download manager installed? Disable its automatic capture in the browser Flux will handle. A system-wide hook can capture requests before Flux's extension sees them. Flux does not alter another application's settings.

Daily use

• Files: click a download link or add a URL. Flux approval offers name, destination, connections, speed limit, immediate start or queueing. If Flux is unavailable before ownership changes, the browser retains the transfer. Later errors after durable handoff stay in Flux.
• Media: choose quality/output on the floating button and send to Flux. Drag the grip anywhere in the tab's visible viewport; arrow keys move it and Home restores its default corner. Positions persist per domain. Outside clicks close the panel; the cross hides the HUD for the page session. The extension popup controls media-button visibility.
• History: search/sort downloads, inspect creation/start/completion times, open/show completed files or drag them into Windows applications.
• Preferences: category routing and clipboard monitoring are opt-in. Explicit destinations override routing. Silent clipboard mode adds to the durable queue without a window.
• Queue completion: exit, sleep, hibernate or shut down after a cancellable 30-second countdown. New work/changed state cancels it; pending, paused or unsuccessful tasks prevent completion. Disabled by default.
• Updates: the main desktop checks GitHub about three seconds after opening; Settings has a manual check. A newer version displays notes and asks for approval before download/install. Flux verifies signatures, checkpoints active tasks and restarts after installation. Startup check errors stay silent.

Languages

English, Mandarin Chinese, Hindi, Spanish, Standard Arabic, French, Bengali, Portuguese, Russian, Urdu, Indonesian, German, Japanese, Nigerian Pidgin, Marathi, Telugu, Turkish, Tamil, Yue Chinese and Vietnamese.

New desktop profiles use the OS locale; extensions use the browser UI locale. Unsupported locales use English. Manual selections persist; Arabic/Urdu use RTL layout.

Privacy and security

No analytics endpoint or remote Flux account. The extension sends selected URLs, titles, bounded manifests and required origin-scoped session headers to the local application. Firefox native transfer requires consent. Credentials are encrypted before durable storage; public task responses omit them. Consent can be withdrawn in settings.

Downloads contact their source; torrents contact peers/trackers/DHT. Enabled Debrid accounts contact their APIs; update checks contact GitHub. Native Messaging uses caller checks, bounded frames and an authenticated user-scoped loopback broker. See Security, IPC and privacy disclosure.

Validation

Windows x64 2.2 has 196 passing automated tests: 118 Rust, 63 extension and 15 frontend. Separate real-browser/desktop checks cover Chrome 155, Firefox 120/157, foreground approval without a browser file chooser, HUD controls, repeated detail-window closing, media ETA, torrent peer transfers, installer repair and uninstall data retention.

Strict TypeScript, production build, Rust formatting and Clippy pass. Production npm audit and modern Firefox manifest lint report zero findings. See full validation and machine-readable evidence.

These are defined regressions, not an every-site guarantee or competitor benchmark. Live paid Debrid entitlements, Linux/macOS application execution, a complete live updater installation round trip and physical OLE drops are outside this local record. Tests do not perform sleep/hibernate/shutdown. A nonfatal upstream WebView2 cleanup warning is recorded separately from passing functional checks.

Development

Use Rust 1.99.0, Node 24.18.0, Tauri prerequisites and native torrent dependencies from the build guide.

git clone https://github.com/Hactor00/Flux.git
cd Flux
npm ci
./scripts/build-torrent-runtime.ps1
npm run tauri dev

npm run dev is a browser preview; native downloads need Tauri. Generated Firefox assets come from shared extension/ sources. Production builds exclude the test harness.

npm test
cargo fmt --all -- --check
cargo test --locked --workspace --all-features
cargo clippy --locked --workspace --all-targets --all-features -- -D warnings

For required media tests, configure FFmpeg/FFprobe and the pinned fixture encoder as described in Contributing. The full encoder is test-only, never shipped. Source export follows Git ignore rules and excludes toolchains, caches, user data and private signing keys.

Documentation and contribution

Use GitHub Issues for reproducible bugs and feature requests. Include versions and reproduction steps; remove private URLs, cookies and authorization headers.

License

Flux's owned code is MIT. FFmpeg/LAME use LGPL, libxml2 uses MIT, yt-dlp uses Unlicense; Node, libtorrent, OpenSSL and other dependencies retain their notices. Distributions include dependency inventories, required notices and media sources. SHA-256 identifies files; it does not replace Authenticode or malware scanning.

Code signing policy

The acknowledgment for approved SignPath-signed releases is: “This project uses SignPath Foundation for code signing.”

Flux is preparing free code signing through SignPath.io, with a certificate provided by SignPath Foundation. Foundation approval and production signing configuration are pending; current 2.2.0 Windows packages do not carry an Authenticode publisher certificate. The existing updater signature is separate.

See the code signing policy for signing scope, maintainer/approver roles and release verification. Privacy Policy URL: Flux privacy disclosure.