Bolt

Fast multi-threaded download manager for Linux, Windows and macOS. Built with Rust and iced.

Features

• Multi-segment downloading -- splits files into up to 8 parallel segments for maximum throughput (auto-scales by file size: 1 segment < 5 MB, 2 < 20 MB, 4 < 50 MB, 6 < 200 MB, 8 for larger)
• Pause, resume & persistence -- stop and continue downloads without losing progress; segment state survives app restarts
• Speed limiting -- configurable global bandwidth cap in KB/s, distributed evenly across active segments
• Concurrent downloads -- control how many downloads run simultaneously (1–10); queued downloads auto-start when slots free up
• Download scheduling -- set a daily time window to auto-start queued downloads
• Proxy support -- HTTP, HTTPS and SOCKS5 proxy with username/password authentication and one-click connection testing
• System tray & background mode -- minimizes to tray on close; live tooltip shows speed and active count; --background flag starts hidden
• Auto-resume on reconnect -- periodic connectivity check (generate_204); retries all failed downloads when network returns
• File categorization -- automatic category detection (Video, Audio, Document, Archive, Image, Application) from file extension
• Download history -- completed downloads are tracked persistently (up to 500 entries) with filename and URL search
• Batch downloads -- paste multiple URLs or import from a text file to queue downloads in bulk
• Browser integration -- extension for Chrome, Edge, Brave, Vivaldi, Firefox and other browsers intercepts downloads, captures cookies and referrer, and sends them to Bolt with a confirmation popup
• Dark / Light / System theme -- three theme modes with full widget styling
• Multi-window -- browser-intercepted downloads each open in their own always-on-top confirmation dialog with Start/Queue/Dismiss
• Auto-start on login -- optional system autostart (Linux .desktop, macOS launchd, Windows registry)
• Cross-platform -- Linux (Wayland + X11), Windows, macOS with native file dialogs

Browser Integration

Bolt intercepts downloads from Chrome/Chromium-based browsers and Firefox. Three components work together:

1. Browser extension (extension/) -- intercepts chrome.downloads.onCreated, cancels the browser download, captures cookies and referrer, sends the request to the native messaging host. Compatible with Chrome, Edge, Brave, Vivaldi, and Firefox (Manifest V3).
2. Native messaging host (bolt-nmh) -- bridges the browser's native messaging protocol (stdin/stdout, 4-byte length-prefixed JSON) to Bolt's TCP IPC server
3. IPC server (inside Bolt) -- listens on localhost:9817 for JSON download requests; each download opens its own confirmation popup

The extension popup provides toggles for:

• Intercept Downloads -- enable/disable download interception
• Forward Cookies -- send browser cookies with the download request (requires optional cookies permission)

Setup

# Build the native messaging host
cargo build --release -p bolt-nmh

# Install the NMH manifest (auto-detects Chrome, Chromium, Brave, Edge, Vivaldi, Firefox)
cd bolt-nmh && ./install.sh <your-chrome-extension-id>

# Alternatively, Bolt auto-installs/updates the NMH manifest on startup
# if an existing manifest is found (dev mode)

Chrome / Chromium-based browsers:

Install from the Chrome Web Store, or load manually:

1. Open chrome://extensions
2. Enable Developer Mode
3. Click Load unpacked and select the extension/ directory

Firefox:

Install from Firefox Add-ons, or load temporarily:

1. Open about:debugging#/runtime/this-firefox
2. Click Load Temporary Add-on
3. Select extension/manifest.json

Building

Prerequisites

• Rust 1.88+ (install via rustup)

Linux (Wayland or X11):

# Debian/Ubuntu
sudo apt install pkg-config libssl-dev libfontconfig-dev \
  libgtk-3-dev libayatana-appindicator3-dev

# Fedora
sudo dnf install pkg-config openssl-devel fontconfig-devel \
  gtk3-devel libayatana-appindicator-gtk3-devel

# Arch
sudo pacman -S pkg-config openssl fontconfig gtk3 libayatana-appindicator

Windows / macOS: No extra system dependencies -- just Rust via rustup.

Build and run

# Debug build
cargo run

# Release build (full workspace: bolt + bolt-nmh)
cargo build --workspace --release

# Run
./target/release/bolt              # Linux / macOS
.\target\release\bolt.exe          # Windows
./target/release/bolt --background # Start minimized to tray

Packaging

Pre-built packages include both bolt and bolt-nmh binaries:

Format	Config
.deb	Cargo.toml [package.metadata.deb] -- package name bolt-dm
.rpm	Cargo.toml [package.metadata.generate-rpm]
AUR	dist/aur/PKGBUILD -- package name bolt-dm-bin

# Build .deb
cargo install cargo-deb
cargo deb

# Build .rpm
cargo install cargo-generate-rpm
cargo generate-rpm

Usage

1. Paste a download URL into the input bar and click Add
2. The file info is resolved and the download appears in the queue
3. Click the play button to start downloading
4. Use pause/resume/cancel buttons to control active downloads
5. Completed files can be opened or their folder revealed
6. Open Settings (gear icon) to configure speed limits, concurrency, scheduling, theme, proxy, and download directory
7. Close the window -- the app minimizes to the system tray
8. Right-click the tray icon to show the window or quit

Architecture

src/
├── main.rs              # Entry point, iced daemon, font loading
├── app.rs               # Application state, message handling, IPC polling
├── message.rs           # Message enum (Elm architecture)
├── model.rs             # DownloadItem, FileCategory, SpeedTracker, etc.
├── settings.rs          # AppSettings, DownloadDatabase, DownloadHistory, ProxyConfig
├── theme.rs             # ColorScheme, ThemeMode, widget styles
├── tray.rs              # System tray icon, menu, tooltip, event polling
├── ipc.rs               # TCP IPC server (localhost:9817) for browser integration
├── nmh.rs               # NMH manifest auto-install for detected browsers
├── autostart.rs         # Platform autostart (Linux/macOS/Windows)
├── view.rs              # UI layout, settings panel, popup confirmation windows
├── download/
│   ├── engine.rs        # Download engine (queue, segments, concurrency, persistence)
│   └── worker.rs        # Segment worker (HTTP streaming, retry, throttling, I/O)
└── utils/
    └── format.rs        # Byte/speed/ETA/filename formatting

bolt-nmh/                # Native messaging host (workspace member)
├── src/main.rs          # Browser NMH ↔ Bolt IPC bridge
├── install.sh           # Linux/macOS install script (Chrome, Edge, Firefox)
└── com.bolt.nmh.json.template

extension/               # Browser extension (Manifest V3, Chrome + Edge + Firefox)
├── manifest.json        # Permissions: downloads, nativeMessaging, storage
├── background.js        # Download interception, cookie forwarding, NMH messaging
├── popup.html           # Extension popup UI
└── popup.js             # Toggle logic, connection status check

Dependencies

Crate	Purpose
iced 0.14	GUI framework (Elm architecture, multi-window, Wayland + X11)
iced_fonts 0.3	Bootstrap icon font
tokio 1	Async runtime (full features)
futures 0.3	Stream utilities for download workers
reqwest 0.11	HTTP client (streaming, rustls-tls, SOCKS5 proxy)
serde / serde_json	Settings, download state, and IPC serialization
tray-icon 0.21	Cross-platform system tray
chrono 0.4	Date/time for scheduling and history
uuid 1	Unique download identifiers
rfd 0.14	Native file/folder dialogs
image 0.25	App icon loading (PNG)
directories 5.0	Platform config/data paths (~/.config/Bolt/)
url 2	URL parsing and validation
anyhow 1.0	Error handling
gtk 0.18	Linux tray support

License

MIT -- see LICENSE for details.