PDF Rider

A fast, lightweight, open-source PDF reader for Windows. Read, annotate, sign, fill forms, and compress — all in a single 5.5 MB portable executable. No installer. No subscription. No telemetry.

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Why PDF Rider?

Most PDF tools are either bloated desktop applications that take minutes to install and gigabytes of disk space, or cloud-based services that upload your documents to a third-party server. PDF Rider is neither.

	PDF Rider	Adobe Acrobat	Online tools
Binary size	5.5 MB	~4 GB	—
Installer required	No	Yes	No
Works offline	Yes	Yes	No
Your files stay local	Always	Yes	No
Price	Free & open source	~€180/year	Freemium
Startup	Instant	Slow	Browser-dependent

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Features

Read

• Crisp rendering powered by PDF.js — text, vectors, and images at any zoom level
• Page navigation with keyboard shortcuts, page number input, and prev/next buttons
• Zoom controls — fit to width, fit to height, snap levels, or type any percentage
• Rotation — rotate pages 90° clockwise
• Drag & drop to open files

Annotate

• Text annotations with full typography controls: bold, italic, underline, size, color, alignment
• Shape annotations — rectangles and circles with stroke color
• Freehand signature — draw directly or insert a signature image
• Layer management — bring to front / send to back
• Annotations are saved as PDF metadata and fully re-editable on reopen

Fill forms

• Interactive form support — text fields, checkboxes, radio buttons
• Keyboard navigation between fields (Tab / arrow keys)
• Filled values are saved back into the PDF

Compress

• Three quality presets: Screen (smallest), Ebook (balanced), Print (high quality)
• JPEG re-encoding, FlateDecode stream compression, metadata stripping, dead object pruning
• Typical result: 35% size reduction with no visible quality loss

Internationalized

• 20 languages — switch instantly in Settings, no restart required
• UI fully translated: English, Français, 中文, हिन्दी, Español, العربية, বাংলা, Русский, Português, اردو, Bahasa Indonesia, Deutsch, 日本語, Kiswahili, मराठी, తెలుగు, Türkçe, தமிழ், Tiếng Việt, 한국어

Windows integration

• Set as default PDF handler directly from the app — no admin rights required
• Print silently from the command line (pdf-rider-portable.exe --print file.pdf)
• Registers both open and print verbs in HKCU

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Download

→ Download the latest release

Single portable .exe, 5.5 MB. Drop it anywhere and run it — no installer, no dependencies.

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Contributing

PDF Rider is built with Rust + TypeScript + Tauri v2. The codebase is intentionally small and straightforward. Contributions are welcome.

Prerequisites

Tool	Minimum version	Install
Rust (stable)	1.77	rustup.rs
Node.js	18	nodejs.org
Tauri CLI	2.x	cargo install tauri-cli
Visual Studio Build Tools	2019+	visualstudio.microsoft.com

Platform: Windows only (the portable .exe uses Windows-specific APIs for printing and file association).

Build

# Clone
git clone https://github.com/pleymor/pdf-rider.git
cd pdf-rider

# Install JS dependencies
npm install

# Run in development (hot-reload frontend, auto-rebuild Rust on change)
npm run tauri dev

# Build a release portable executable
npm run tauri build
# Output: src-tauri/target/release/pdf-rider-portable.exe

Architecture

pdf-rider/
├── src/                        # TypeScript frontend (Vite + PDF.js)
│   ├── main.ts                 # App entrypoint, event wiring
│   ├── tauri-bridge.ts         # All invoke() wrappers with types
│   ├── toolbar.ts              # Toolbar component & events
│   ├── compress-modal.ts       # Compression modal
│   ├── i18n.ts                 # 20-language translation table
│   └── styles/app.css          # All styles
├── src-tauri/
│   ├── src/
│   │   ├── lib.rs              # App state, Tauri setup, command registration
│   │   ├── commands/           # Tauri command handlers (one file per feature)
│   │   │   ├── compress.rs     # compress_pdf command
│   │   │   ├── pdf.rs          # get_page_count, save_annotated_pdf, read_annotations
│   │   │   ├── dialog.rs       # open/save dialog commands
│   │   │   └── shell.rs        # print, URL open, file association
│   │   └── pdf/
│   │       └── compress.rs     # PDF compression logic (lopdf)
│   └── Cargo.toml
├── specs/                      # Feature specifications (one folder per feature)
└── index.html                  # Single-page app shell

How a feature works end-to-end:

1. User clicks a toolbar button → toolbar.ts emits a typed event
2. main.ts handles the event, calls a wrapper in tauri-bridge.ts
3. tauri-bridge.ts calls invoke("command_name", { ...args })
4. Tauri routes to the matching #[tauri::command] fn in commands/
5. The Rust handler processes the PDF (via lopdf or the filesystem) and returns a result
6. The result is displayed as a toast or used to update the UI

Code quality checks

Run these before opening a PR — both must pass:

# Rust: lints and type checks
cd src-tauri && cargo clippy -- -D warnings

# TypeScript: type checks (no emit)
npx tsc --noEmit

Branching & commit conventions

What	Convention
Branch name	NNN-short-description (e.g. 004-dark-mode)
Commit message	Imperative, present tense: Add dark mode toggle
One commit per PR	Squash before merging
PR title	Same as the squashed commit message

Feature branches are numbered sequentially. Pick the next available number from the existing specs/ directories.

Opening a PR

1. Fork the repo and create a branch from main
2. Make your changes — keep PRs focused on a single feature or fix
3. Run cargo clippy and tsc --noEmit, fix any warnings
4. Open a PR with a clear description of what and why
5. Link the relevant spec from specs/ if one exists

Good first issues

Check the open issues — issues labeled good first issue are a great place to start.

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License

MIT — see LICENSE for details.