Bifrost sends files of any size straight from one device to another, Windows or Android, end-to-end encrypted. Every transfer ends with a receipt that shows the route it took and what was kept along the way: nothing.
Free and open source under the MIT license. No account, no analytics, no cloud copy.
A live simulation. Try pausing, or cutting the connection.
Anyone can write "private" on a landing page. Bifrost gives you a receipt for every file instead, stored on your device, that says exactly how it travelled. Here is a real one, line by line.
When a new device asks for access, both screens show five words made from the two devices' keys. Read them to each other. If they match, the connection is between you two and no one else. If anyone tried to sit in the middle, the words would be different.
A calendar shows each day as a dot sized by how much moved. Hover a day to see the files, check who you trade the most data with, and what kind of files they are. All of it is worked out on your device from your own receipts.
Each file travels once, from the sender's disk to the receiver's, and leaves a matching receipt on both.
The sender picks one folder. Nothing outside it can be seen or opened.
Copy a link-style invitation or read out a 12-character code. You approve each new device.
Check the five safety words match, then browse the folder like a file manager and choose where to save.
Each megabyte is hash-verified on arrival, and the whole file once more before it is named.
Progress is written to disk every megabyte, after it is verified. A dropped connection, a pause, a closed laptop or a power cut loses at most the block in flight. Downloads wait for the sender to come back and continue on their own.
Bifrost uses QUIC with BBR congestion control and many parallel streams, so a Dhaka to Berlin link stays full instead of collapsing at the first lost packet. A live graph shows both directions and marks every pause, reconnect and route change. It runs at low CPU priority and never loads a whole file into memory.
The receiver sees the shared folder with names, sizes and dates, searches it, and downloads single files or whole folders. Big folders load as you scroll, so a directory with thousands of files stays quick.
Send from a PC to a phone, from a phone to a PC, or phone to phone. On Android, transfers keep running with the screen off and show their progress in a notification.
Two devices on the internet need a little help to find each other. Here is everything that help can see, and everything it can't.
| Capability | Bifrost | Cloud share links | Chat and messaging apps |
|---|---|---|---|
| File size limit | None | Usually a few GB | Usually 2 GB or less |
| Travels over the internet | Once, device to device | Twice: upload, then download | Twice, through their servers |
| Copy kept on a server | Never | Until the link expires | Often |
| Resumes after a drop | From the last megabyte | Sometimes | Rarely |
| Verifies every byte | Yes, block by block | Varies | Varies |
| Both devices online | Required | Not required | Not required |
Bifrost trades the convenience of an always-on server for privacy and no size limits: the sender has to stay online while the receiver downloads.
Latest release. Free, no account needed.
Bifrost is new and not yet code-signed by a certificate authority, so Windows SmartScreen may show “Windows protected your PC”: choose More info, then Run anyway. On Android, allow your browser or file manager to install apps when asked; if Play Protect shows a warning, choose More details, then Install anyway. Every release lists SHA-256 checksums so you can confirm the file is genuine.
Bifrost is MIT licensed. The transfer engine is a Rust library with end-to-end tests for interruptions, crashes, corruption and source changes; the apps use Tauri with a React interface. Issues, ideas and pull requests are welcome.
Bifrost
# Build and run from source
git clone https://github.com/MisbahKhan0009/Relayless
cd Relayless && npm ci
npm run tauri dev
# Engine tests: real transfers, pauses,
# crashes, corruption, source changes
cargo test -p relayless-core --releaseYes, while the transfer runs. If either one goes offline, the download waits and continues from where it stopped when both are back.
Some networks, mobile data in particular, block direct paths. Bifrost tries direct first and, after about 15 seconds, continues through a public relay. The data stays end-to-end encrypted, so the relay can't read or keep it, and it switches back to direct as soon as a path opens. The receipt shows how much went through the relay. If you'd rather wait for a direct path, choose Direct only in Settings.
No. Files are streamed from disk in small blocks, so a 500 GB file uses the same memory as a 5 MB one. You need enough free space on the receiving side.
As fast as the slower of the two connections allows, which is usually the sender's upload speed. Bifrost is tuned to keep long-distance links full.
No. They can only list and download from the folder you shared, and only after you approve their device. You can stop sharing or remove a device at any time.
Only in the app's database on your device. Nothing is synced or uploaded. You choose how long it is kept, can keep it without file names, and can clear it at any time in Settings.
They let two people confirm, out loud or over a call, that their devices are talking to each other directly. They are derived from both devices' keys, so a device in the middle would produce different words.
No. Bifrost is free and open source. There is no account and no paid tier.