Simple first. Local first.

How SEYFR Sends a File

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Mac · Windows · Linux · Android · iPhone

Your file starts on your device and ends on the receiver's device. The QR code contains no file data—it only carries directions and a 32-byte fingerprint so the receiver can request and verify the right content.

SEYFR running on a generic phone and laptop with the message You can trust us and move files without the detour SEYFR 1.x UI

Trust is architectural

Your files do not take a cloud-storage detour.

SEYFR keeps the selected content on the sender until the receiver requests it. SEYFR uses Iroh to connect devices directly when possible, with an end-to-end encrypted relay fallback when a direct path is unavailable. The relay forwards the transfer; it does not become a JITPOMI cloud drive.

One transfer core, native apps
The same Rust transfer rules power the supported Android, Apple, Windows, and Linux apps.
JFFI Developer Framework (Power of Rust, Charm of Native) macOS (SwiftUI) Android (Compose) Windows (WinUI 3) iOS (SwiftUI) Linux (GTK 4) JFFI & UniFFI Bridge Connects each native app to the shared Rust core Shared Rust Core (seyfr-core) Local storage, content addressing, transfer and file checks Connection Routing Relay helps connect, then steps back when direct works iroh Content-Addressed Blobs 32-byte BLAKE3 address; verified while streaming iroh-blobs
The JFFI Philosophy: Power of Rust, Charm of Native

Use the Right Tools for the Job

SEYFR keeps the complicated parts in one shared Rust core while each platform keeps a familiar native interface.

  • On-device Core: File preparation, local storage, integrity checks, and transfer rules run on the device.
  • Native Screens: Uses the interface technology of each supported platform rather than a shared website wrapper.
  • One Set of Rules: The shared core keeps transfer behavior consistent across supported platforms.
R
NATIVE UI ON DEVICE
Native by design

Familiar on Every Platform

SEYFR uses native interfaces on each supported platform, backed by a shared Rust transfer core:

  • Native Controls: Uses platform-native interface technology instead of presenting the transfer screen as a website wrapper.
  • Shared Core: The same Rust transfer rules are used across supported platforms while each app keeps its platform-specific interface.
  • Platform Fit: Each app follows the conventions of its operating system.
Security First

The Rust Core Vault

Our Rust core applies the same destination and file-handling checks across supported platforms:

  • Destination Path Validation: Uses path_jail to keep received paths inside the destination the user selected and reject traversal attempts.
  • Safer File Handling: Rust memory safety reduces important classes of memory errors; it does not make software immune to every defect.
  • Folder Collection: Walks non-empty folders, skips nested hidden directories and node_modules, and preserves relative file paths.
Firewall Firewall BEST PATH AVAILABLE
Adaptive Delivery

Peer-to-Peer, Direct When Possible

SEYFR does not use a JITPOMI cloud drive. Iroh finds the best available path between the sender and receiver.

  • Nothing is stored in the QR code.
    The ticket only tells the receiver how to request and verify the selected content.
  • Direct when the network allows it.
    Iroh searches for the best path between the sender and receiver.
  • Encrypted relay fallback.
    If a direct path fails, a relay forwards the end-to-end encrypted transfer without storing the file.
Read the protocol details
The ticket includes connection information, a 32-byte BLAKE3 root hash and the HashSeq format—not the file or its metadata. Iroh attempts NAT traversal and local-network discovery through mDNS. Iroh reports that roughly 9 out of 10 network configurations permit a direct connection, although this is not guaranteed for every SEYFR transfer. BLAKE3 verification checks streamed data incrementally. Read Iroh's NAT traversal documentation.

Phone to computer

Send the original file to the computer you already use.

Move photos, videos, folders and documents between supported devices—without creating an account or uploading them to cloud storage first.

Download SEYFR free Ask if SEYFR supports your setup →

Concept artwork. Actual transfer speed depends on your devices and network.

Concept illustration of SEYFR transferring files between a generic phone and laptop; interface panels and speed are illustrative, not actual product claims