File Transfer

PureSend provides fast and secure file transfer capabilities with multiple transfer modes.

How It Works

PureSend supports three transfer modes:

P2P Direct Transfer

1. Device Discovery: Auto-discover other PureSend devices on the LAN via mDNS protocol
2. Connection Establishment: Establish direct HTTP connection via device IP and port
3. Security Handshake: Use P-256 ECDH key exchange to establish encrypted channel (optional)
4. Data Transfer: Files are automatically chunked with optional encryption and compression

Web Download (Link Sharing)

1. The sender starts an HTTP server and shares files
2. A download link and QR code are generated
3. The receiver opens the link in any browser to download
4. Supports PIN protection and access approval

Web Upload

1. The receiver starts an HTTP upload server
2. An upload link and QR code are generated
3. The sender opens the link in a browser to upload files
4. Supports per-IP approval and chunked upload

Features

Multiple Content Types

• Files: Select any type of file for transfer
• Folders: Select entire folders for batch transfer
• Clipboard: Transfer clipboard contents directly
• Text: Quick text message sending
• Media: Select photos/videos from media library
• Apps: Share installed apps (Android)

Transfer Capabilities

• Resume Transfer: Resume interrupted transfers from the breakpoint
• Chunked Transfer: Large files are automatically chunked (1MB/chunk) with parallel processing
• Dynamic Compression: Smart compression based on zstd algorithm, automatically determines whether to compress
• Transfer Speed: Can reach 100Mbps+ within LAN

Device Discovery

• mDNS Auto-Discovery: Automatically discover PureSend devices on the same LAN
• Manual Add: Support adding devices manually via IP address

Network Adaptation

• Automatic Network Change Detection: Real-time monitoring of Wi-Fi switching, wired/wireless switching, IP address changes, etc.
• Automatic Link Update: When network changes, Web download and Web upload share links and QR codes automatically update to new IP addresses
• Automatic Device Discovery Restart: Automatically restarts mDNS device discovery service when network changes to ensure discoverability on the new network
• Seamless Experience: Server binds to 0.0.0.0, no need to restart service after network switch, only updates display layer information

Security

Transfer Encryption

• AES-256-GCM end-to-end encryption protects transfer data
• P-256 ECDH key exchange (HTTP transfer mode, compatible with browser Web Crypto API)
• X25519 key exchange (P2P transfer mode)
• Encryption can be enabled/disabled in settings

Access Control

• PIN Protection: Web download links can be protected with PIN code
• Access Approval: Support manual approval or auto-accept for transfer requests
• IP Approval: Web upload mode supports per-IP address approval

Privacy Protection

• File data is transferred only within LAN or Wi-Fi direct
• No external servers or cloud relay involved
• Privacy mode available to disable transfer history

Transfer History

• Automatically records detailed information for each transfer (direction, status, file list, duration, etc.)
• Filter by direction (send/receive) and status (completed/failed, etc.)
• Sort by time, size, etc.
• Privacy mode can disable history recording

Tips

Improve Transfer Speed

1. Ensure devices are on the same LAN
2. Turn off VPN and proxy
3. Use 5GHz WiFi network
4. Enable dynamic compression (especially effective for text-based files)

Cross-Platform Transfer

Supports file transfer between any platforms:

• macOS ↔ Windows
• Linux ↔ Android
• Desktop ↔ Mobile
• Any device ↔ Browser (via Web Download/Upload)