Fast, secure, serverless file transfer.
Send any file straight from your computer to someone else's over an encrypted link. No upload to the cloud, no account, no size limit.
Version 2.0 adds an end-to-end encrypted relay, so a transfer gets through even when a direct connection cannot, without the server ever being able to read your file.
Free for personal use. Business licensing and self-hosted servers are available.
Why NetXfer
Fast by design
Transfers run over SRT, a UDP based protocol built for moving media over the open internet. It fills the bandwidth you have and recovers lost packets without slowing to a crawl.
Private by default
Your file goes from your disk to the receiver's disk and nowhere else. There is no account to create, no cloud copy to forget about, and nothing for anyone to mine.
Always gets through 2.0
Direct, then rendezvous, then an encrypted relay. If the link drops, the transfer resumes where it stopped, even after a restart, and MD5 confirms the result.
The biggest NetXfer release yet
NetXfer 2.0 is a new transport, a new server and a new fallback, built around one rule that has not changed: nobody but the receiver can read your file.
When neither a direct nor a rendezvous connection is possible, the sender streams the file through the server in 8 MB chunks. Each chunk is sealed with AES-256-GCM before it leaves the sender, so the server stores and forwards ciphertext it cannot open, and deletes each chunk the moment it is delivered.
Transfers now use SRT (Secure Reliable Transport) in file mode. AES-256 is not optional and cannot be switched off. A connection with the wrong passphrase is rejected before any data is exchanged.
The receiver remembers how much of a file it already has. A dropped connection, a laptop lid closed, even a reboot: the next connection picks up at the last byte written instead of starting over.
Every request to the rendezvous server carries a key derived from the transfer packet. The server stores only a hash of that key, so only someone holding the packet can read or change a record. Repeated bad keys are rate limited.
Turn on "Validate with MD5" and the receiver checks the finished file against the sender's checksum, so what lands on the editor's desk is exactly what left the field.
The sender can remove its record from the server at any time, records not refreshed for seven days are deleted automatically, and relay chunks never outlive the download they belong to.
Direct first. Relay only as a last resort.
The reason people chose NetXfer in the first place has not changed. The file goes computer to computer. The server, when it is involved at all, is a matchmaker, not a mailbox.
Direct and rendezvous: the file never touches a server
When the two computers can see each other, NetXfer connects straight to the sender and starts pulling the file. That is the whole story for most office, campus and data centre transfers.
When one or both sides are behind a home router, a corporate firewall or carrier NAT, NetXfer uses netxfer.com as a rendezvous point. Each side publishes only its addresses and ports under a random id; the server hands them across and the two apps punch through to each other. The file itself still travels directly, encrypted.
Prefer not to involve netxfer.com at all? Turn the rendezvous server off and swap the transfer packets over your own secure channel instead.
How rendezvous works| Mode | Your file | What netxfer.com sees |
|---|---|---|
| Direct | Computer to computer | Nothing |
| Rendezvous | Computer to computer | Addresses and ports, a random id, the file name and size |
| Relay 2.0 | Encrypted chunks pass through | Ciphertext it cannot open, deleted on delivery |
Relay: for the networks that block everything New
Some networks allow nothing but web traffic out. Before 2.0, a transfer between two such networks simply could not happen. Now the receiver, after trying direct and rendezvous, can ask the sender to upload through the server over HTTPS while it downloads the same chunks from the other side.
What makes this different from a cloud drop box is what the server holds. Every chunk is encrypted by the sending app with a key derived from the encryption phrase in the transfer packet, a phrase the server never receives. The chunk's position, the file size and its timestamp are authenticated too, so a chunk cannot be altered, swapped or reordered without the receiver noticing and refusing it.
The relay is optional on both ends. The sender can switch it off in Preferences, the receiver can decline it, and a self-hosted server can leave it disabled entirely.
How the encrypted relay worksFree for personal use. Built for professional use.
NetXfer started as the file transfer engine inside Drastic's Net-X-Code servers, the same systems that move media for major broadcasters and studios. The desktop app is free for personal use, and the full stack is there when you need it.
NetXfer Free
Everything in the app, for non-commercial use.
- Windows, macOS and Linux
- Direct, rendezvous and encrypted relay transfers
- Resume, MD5 verification, unattended shutdown
- Uses netxfer.com for rendezvous and relay
- No business or institutional use
NetXfer Commercial and Net-X-Code
Licensed for work, with your own infrastructure.
- Commercial licence for the desktop app
- Run your own rendezvous and relay server on your domain
- Net-X-Code Server: capture, convert, transfer and archive with a REST API
- Security and monitoring tools, priority support
The transfer engine behind the big screens
NetXfer is part of the Net-X-Code Server family. These are some of the organisations that run it every day.
Net-X-Code provides the capture, convert, transfer and archive backbone for ESPN's main facility in Bristol.
The NBA captures every game, archives, and performs partial file restores with Net-X-Code and NetXfer server systems.
NBCUniversal uses Net-X-Code and FlowCaster to send and capture IP signals throughout their facilities.
Peloton captures all the action on Net-X-Code servers, with edit while capture, clipping and transfers.
MGM relies on Drastic's Net-X-Code tools for media conversion and secure movement of content.
Tyler Perry Studios moves production media between stages and post with Drastic's Net-X-Code servers.
Frequently asked questions
Short answers here. The long ones, with the protocol details, are on the how it works page.
Yes, for personal use, on Windows, macOS and Linux, with no account and no file size limit. Business and institutional use needs a commercial licence, on its own or as part of Net-X-Code Server.
- Transfers run over SRT with AES-256 encryption that cannot be turned off.
- An end-to-end encrypted relay through the server when direct and rendezvous connections both fail.
- Interrupted transfers resume from the last byte written, even after a restart.
- Optional MD5 verification of the finished file.
- Every server request is authenticated with a key only the two apps can derive; the server stores just a hash of it.
- A rebuilt netxfer.com with rate limiting, automatic clean-up and no secrets in the code.
With a direct or rendezvous connection, never. The file goes from the sender's disk to the receiver's disk over an encrypted SRT link, and netxfer.com, if it is used at all, only passes addresses between the two apps.
Only when neither of those works, and both sides allow it, does the 2.0 relay pass the file through the server. Even then the server holds nothing but encrypted 8 MB chunks it cannot open, a few at a time, and deletes each one as soon as the receiver has it. There is no copy to download later, and the sender has to be online for the whole transfer.
No. The sending app seals every chunk with AES-256-GCM under a key derived from the encryption phrase in the transfer packet. That phrase is only ever shared between the sender and the receiver; the server is given a separate, one-way hash to recognise requests with, and cannot work backwards from it.
The encryption also covers the chunk's index, the file size and its timestamp, so a chunk that is altered, duplicated or moved fails verification and is thrown away by the receiver. Details are on the how it works page.
When the rendezvous server is enabled, a record holds:
- a random file id and a hash of the access key,
- the file name and size,
- the sender's local and public addresses and ports,
- the receiver's addresses while a rendezvous is being arranged.
Never the encryption phrase, and never the contents of your file. The sender can delete the record at any time, and any record not refreshed by its sender for seven days is removed. The app may also ask netxfer.com for your public IP address, the same way a "what is my IP" site works, over HTTPS.
A short block of text called the transfer packet, or the same thing saved as an .xfer file. It contains the sender's addresses, a random file id, the encryption phrase and the file size. The receiver pastes it or drops it onto NetXfer and the transfer starts.
Treat the packet like a key: send it over a channel you trust, such as an encrypted messenger. Anyone with the packet can receive the file while the sender is sharing it.
Yes. Untick "Use a rendezvous server" in Preferences and NetXfer only makes direct connections, which is all you need inside one network or when the sender has a reachable address. Commercial customers can point the app at their own rendezvous and relay server instead, so nothing ever leaves their domain.
The receiver keeps trying, direct, then rendezvous, then relay, and every new connection resumes from the bytes already on disk. That holds across a restart of the app or the computer. With "Validate with MD5" on, the finished file is checked against the sender's checksum before it is declared done.
Yes. The encryption key never leaves the two apps, so the receiving end has to be able to decrypt, and that means the free NetXfer app on Windows, macOS or Linux. It takes a minute to install and there is nothing to sign up for.
For now, yes: netxfer.com keeps a compatibility interface for earlier releases. They cannot use the new relay, resume or authenticated records, and both ends of a transfer need the same generation. The app checks for updates itself, or you can download 2.0 from this page.
Work use needs the commercial version of NetXfer or a Net-X-Code Server, which includes it along with capture, conversion, partial file restore and a REST API. See the business page or contact sales@drastictech.com.
Net-X-Code Server is Drastic's server suite for baseband and IP video, file conversion, partial file restore, closed captions and file transfer. It runs on standard Windows and Linux servers or VMs, alone or in clusters, with local, network and cloud storage, under a web UI or a REST API. See www.netxcode.com.
FlowCaster is the live counterpart to NetXfer: low latency, secure point to point video and audio for remote review and production, from Adobe, Avid, DaVinci and other hosts, SDI, HDMI, SMPTE 2110 and the desktop, with server side conversion between RTMP, RTP, UDP, SRT, RIST and more.
NetXfer, Net-X-Code, FlowCaster, videoQC and Drastic / Drastic Technologies are trademarks of Drastic Technologies Ltd. All software downloaded from this site is Copyright 2019-2026 Drastic Technologies Ltd. All rights reserved. Customer logos belong to their respective owners.
Install it. Drop a file. Send the packet.
Both ends install the free app. The sender drags a file in and copies the transfer packet. The receiver pastes it. That is the whole workflow, and the app walks you through it in 11 languages.
Also available: 32-bit Windows. The user manual (PDF) covers every preference. The app checks this site for updates itself.
