Private, encrypted cloud sync using S3-compatible storage.
Your data. Your storage. Your keys. No middleman.
sync2bucket is an open-source, end-to-end encrypted sync solution that turns any S3-compatible storage provider into your private cloud. Unlike traditional cloud storage services, sync2bucket gives you complete control over where your data lives and who can access it.
Modern cloud storage services like Dropbox, Google Drive, and OneDrive are convenient, but they come with significant trade-offs:
- Privacy concerns: Your files are accessible to the provider, their employees, and potentially government requests
- Vendor lock-in: Moving your data between providers is difficult or impossible
- Cost at scale: As your storage needs grow, subscription costs quickly add up
- Limited control: You're at the mercy of the provider's policies, terms, and continued operation
- Feature bloat: Most users don't need collaboration tools, AI features, or multi-user management
Self-hosting solutions like Nextcloud and NAS systems offer more control, but introduce new problems:
- Complexity: Require server maintenance, security updates, and technical expertise
- Multi-user overhead: Most features are designed for teams, not individuals
- Always-on requirement: Need a server running 24/7 at home or in the cloud
- Single point of failure: If your server goes down, so does your access
- Port forwarding and networking: Complex setup for remote access
sync2bucket bridges the gap between convenience and control:
Privacy First
- Files are encrypted on your device before leaving it
- Compatible with the battle-tested rclone crypt format
- Even the storage provider cannot read your files
- Fully open source - audit the code yourself
Use Any S3 Provider
- Works with AWS S3, Backblaze B2, Wasabi, Cloudflare R2, and any S3-compatible API
- No vendor lock-in - switch providers anytime
- Pay only for storage you use
- Competition between providers keeps costs low
Simple for Single Users
- No server to maintain
- No complex multi-user features you don't need
- Just sync, encrypt, and forget
- Native apps that feel at home on each platform
Cost Effective
- Backblaze B2: ~$6/TB/month (vs Dropbox: $12/TB/month)
- Wasabi: ~$7/TB/month with free egress
- Cloudflare R2: $15/TB/month with zero egress fees
- Only pay for what you use, no minimum commitments
Privacy-conscious individuals who want control over their data without trusting a third-party provider.
Cost-conscious users who have outgrown free tiers but don't want expensive subscriptions.
Power users who already use rclone and want a native GUI experience across all their devices.
Developers and technical users who want to automate backups and sync workflows.
Anyone who values simplicity over feature bloat and complexity.
- End-to-end encryption using NaCl SecretBox (XSalsa20-Poly1305)
- rclone crypt compatibility - interoperate with existing rclone setups
- Cross-platform sync with native apps for iOS, Android, macOS, Windows, and Linux
- S3-compatible storage - works with any provider supporting the S3 API
- Conflict resolution - intelligent handling of files modified on multiple devices
- Selective sync - choose which folders sync to which devices
- CLI and daemon for automation and scripting
- Open source (GPL v2) - audit the encryption yourself
sync2bucket is built on a few core principles:
User Freedom: Your data belongs to you. We give you the tools to control it completely.
Privacy by Design: Encryption happens on your device. We never see your keys or unencrypted data.
Simplicity: Solve one problem well. We're not trying to be Dropbox, Notion, and Slack combined.
Open Source: Trust through transparency. The code is open, the crypto is auditable.
Sustainability: Everything is free and open source. Optional donations support continued development.
- Choose your storage: Select any S3-compatible provider (Backblaze B2, Wasabi, AWS S3, etc.)
- Create a vault: Set up an encrypted vault with a password
- Sync your files: Files are encrypted locally and synced to your S3 bucket
- Access anywhere: Install sync2bucket on all your devices for seamless access
Behind the scenes:
- Files are encrypted using the rclone crypt format before upload
- Filenames are encrypted and obfuscated
- The sync engine detects local and remote changes
- Conflicts are handled intelligently
- Everything happens locally - no middleman server
| Feature | sync2bucket | Dropbox | Nextcloud | rclone |
|---|---|---|---|---|
| Privacy | ✅ E2E encrypted | ❌ Provider access | ✅ Self-hosted | ✅ Encrypted |
| Cost (2TB) | ~$12/year | ~$144/year | Server costs | Free |
| GUI Apps | ✅ Native (free) | ✅ Native (paid) | ✅ Web/mobile | ❌ CLI only |
| Server Required | ❌ No | ❌ No | ✅ Yes | ❌ No |
| Setup Complexity | Low | Very Low | High | Medium |
| Single User Focus | ✅ Yes | ❌ Multi-user | ✅ Yes | |
| Mobile Support | ✅ Native | ✅ Native | ❌ No | |
| Open Source | ✅ GPL v2 | ❌ No | ✅ AGPL | ✅ MIT |
# Install from source
cargo install sync2bucket-cli
# Or download pre-built binary
wget https://github.com/yourusername/sync2bucket/releases/latest/download/s2b-linux-x64
# Create a vault
s2b init ~/Documents --bucket my-encrypted-bucket --provider backblaze
# Sync
s2b sync ~/DocumentsPerfect for:
- Automation and scripting
- Server/headless systems
- Advanced users
- Integration with other tools
Beautiful native applications with:
- 🎨 Platform-native UI
- 🔄 Background sync
- 📊 Visual sync status
- ⚙️ Easy setup wizard
- 💾 System tray/menu bar integration
Download (All Free!):
- Apple App Store (MacOS, iOS, & iPadOS AiO) - Free
- Google Play Store - Free
- Microsoft Store - Free
- Linux - Build from source
All apps are free and open source (GPL v2). Optional in-app donations or GitHub Sponsors support continued development.
crates/- Rust core library, CLI, FFI bindings, and daemonplatforms/- Native UI applications for each platformdocs/- Project website
cd crates
cargo build --releaseSee platform-specific READMEs:
- Encryption: NaCl SecretBox (XSalsa20-Poly1305)
- Key derivation: scrypt
- File format: Compatible with rclone crypt v1
- Storage: Any S3-compatible API
- Sync engine: Custom Rust implementation
- Mobile FFI: uniffi-rs for Swift/Kotlin bindings
v0.1 - MVP (Current)
- Core sync engine
- CLI tool
- rclone crypt compatibility
- Basic S3 support
v0.2 - Native Apps
- iOS app
- Android app
- macOS app
- Windows app
- Linux GTK app
v0.3 - Enhanced Features
- Selective sync
- Bandwidth throttling
- Version history
- Share links (encrypted)
v1.0 - Production Ready
- Full test coverage
- Security audit
- Performance optimization
- Comprehensive documentation
We welcome contributions! See CONTRIBUTING.md for guidelines.
Areas where we need help:
- Testing on different S3 providers
- Platform-specific UI improvements
- Documentation
- Translations
- Bug reports
The entire project is licensed under GPL v2 - this includes:
- Core library
- CLI tool
- FFI bindings and daemon
- All native platform applications
Everything is free to use and modify. Pre-built binaries are available at no cost through app stores. Optional donations help support continued development.
sync2bucket takes security seriously:
- Open source code for transparency
- Compatible with audited rclone crypt format
- Uses well-established cryptography (NaCl)
- No telemetry or phone-home functionality
Found a security issue? Please email [email protected] (do not open a public issue).
sync2bucket stands on the shoulders of giants:
- rclone - Inspiration and crypto format compatibility
- Cryptomator - Proof that open source encryption works
- Syncthing - Inspiration for decentralized sync
- The Rust community for excellent libraries