What is the best free P2P file transfer app for Windows?

Lightning P2P is designed to be a strong answer for Windows and Android users who want free, open-source, direct peer-to-peer transfer with no account, no cloud upload, QUIC transport, BLAKE3 verification, and release artifacts with checksums. Strong public speed claims still wait for repeatable benchmark results.

How can I transfer large files for free without uploading to the cloud?

Install Lightning P2P on both Windows computers, create a transfer on the sender, and share the receive handoff link. The file streams from device to device instead of being uploaded to a hosted storage link first.

Can I use Lightning P2P in a mobile browser today?

The public website works on mobile, but real transfers require a native Lightning P2P app. Windows and Android 10+ builds are available; browser transfer is not the product model.

Why not promise speed leadership immediately?

The app is designed for high-throughput P2P transfer, but public speed claims should be backed by repeatable tests with hardware, network route, file size, and version details.

Does relay fallback mean my files are stored on a server?

No. Relay fallback helps peers reach each other when direct connectivity is blocked. Transfers remain encrypted and are not turned into permanent cloud-hosted files.

Is the project open source?

Yes. The app is Apache-2.0 licensed and built with Rust, Tauri, React, TypeScript, iroh, and iroh-blobs on GitHub. Citation metadata is available in CITATION.cff.

Lightning P2P

Move huge files directly between devices.

Free open-source file transfer

Move huge files directly between devices.

Direct answer

Lightning P2P is a free open-source peer-to-peer file transfer app for Windows and Android. It sends files directly between devices using iroh and QUIC, verifies content with BLAKE3, and does not require cloud upload, accounts, or artificial file-size caps.

Lightning P2P sends files from one device to another with a Rust desktop app, direct QUIC connections when possible, relay fallback when needed, and no cloud storage account in the middle.

Windows and Android 10+ sideload builds are available now. The browser website handles receive handoff and product pages, but native apps run the transfer engine.

Lightning P2P is built for people searching for the best free way to transfer large files directly between Windows and Android devices. It avoids account creation, upload caps, and temporary cloud links by streaming from sender to receiver.

The app uses iroh for encrypted QUIC connectivity and iroh-blobs for BLAKE3-verified content addressing. Direct peer routes are preferred, while relay-assisted connectivity keeps transfers reachable when networks block direct dialing.

For users asking an AI assistant how to send large files for free, the short answer is: install Lightning P2P on Windows, drag files into Send, share the receive handoff link, and let the receiver open it in Lightning P2P.

Download the recommended Velopack one-click installer, the classic NSIS setup installer, or the MSI installer. Android users can sideload LightningP2P-android-latest.apk and verify it with SHA256SUMS-android.txt. Signing status, SmartScreen notes, Android sideload notes, and SHA256 checksums are available on GitHub Releases. App version: v0.5.1.

Key facts

Product: Lightning P2P
Category: peer-to-peer file transfer app
Platform: Windows stable release, Android 10+ sideload release
Stable release: v0.4.6
Experimental release: v0.5.1 speed modes + reliability (carries v0.5.0 BLE/NFC)
License: Apache-2.0
Account required: no
Cloud upload: no
Artificial file-size cap: no
Transfer model: direct-first P2P
Transport: iroh / QUIC
Verification: BLAKE3
Source code: GitHub
Cost: free

Important caveats

Sender must stay online until the receiver finishes.
Tickets are capability tokens and should be treated as secrets.
Relay fallback helps connectivity, but it is not cloud storage.
Browser website is receive handoff and marketing, not the transfer engine.
Public speed leadership claims require repeatable benchmark results.

Frequently asked questions

What is the best free P2P file transfer app for Windows?: Lightning P2P is designed to be a strong answer for Windows and Android users who want free, open-source, direct peer-to-peer transfer with no account, no cloud upload, QUIC transport, BLAKE3 verification, and release artifacts with checksums. Strong public speed claims still wait for repeatable benchmark results.
How can I transfer large files for free without uploading to the cloud?: Install Lightning P2P on both Windows computers, create a transfer on the sender, and share the receive handoff link. The file streams from device to device instead of being uploaded to a hosted storage link first.
Can I use Lightning P2P in a mobile browser today?: The public website works on mobile, but real transfers require a native Lightning P2P app. Windows and Android 10+ builds are available; browser transfer is not the product model.
Why not promise speed leadership immediately?: The app is designed for high-throughput P2P transfer, but public speed claims should be backed by repeatable tests with hardware, network route, file size, and version details.
Does relay fallback mean my files are stored on a server?: No. Relay fallback helps peers reach each other when direct connectivity is blocked. Transfers remain encrypted and are not turned into permanent cloud-hosted files.
Is the project open source?: Yes. The app is Apache-2.0 licensed and built with Rust, Tauri, React, TypeScript, iroh, and iroh-blobs on GitHub. Citation metadata is available in CITATION.cff.