WebRTC

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You’ve probably used file transfer tools that upload your files to a server before the other person can download them. A different approach, peer-to-peer (P2P) transfer, lets files move directly between two browsers without being uploaded or stored anywhere. This is how BeamQR File Transfer works, and the technology behind it is called WebRTC.

What is WebRTC?

WebRTC stands for Web Real-Time Communication. It’s an open standard built into all modern web browsers, including Chrome, Firefox, Safari and Edge, that lets browsers communicate directly with each other in real time.

WebRTC was originally designed for video and voice calls in the browser, so you can join a call without installing a separate app. Services like Google Meet use it every day. But it can also carry data, including files, directly between two browsers.

Because WebRTC is built into the browser itself, no plugin or extension is needed. Any modern browser supports it automatically.

How Traditional File Sharing Works

In a typical file sharing service:

  1. You upload your file to a company’s server (WeTransfer, Google Drive, Dropbox)
  2. The file is stored on that server
  3. You send a link to the recipient
  4. They download the file from the server

Your file goes: Your device → Server (stored) → Recipient’s device

This works, but it means a copy of your file is stored by a third party, sometimes for days or indefinitely. It also means the transfer happens twice: once at your upload speed, then again at the recipient’s download speed.

How Peer-to-Peer Transfer Works

With WebRTC:

  1. One browser creates a session ID (BeamQR shows it as a QR code)
  2. The second browser connects to that session ID, for example by scanning the code
  3. WebRTC sets up an encrypted channel between the two browsers
  4. Files flow from one browser to the other through that channel

Your file goes: Your device → Recipient’s device

The file is never uploaded to a storage server, and no copy is kept anywhere except on the two devices.

The Role of the Signaling Server

Before two browsers can talk directly, they need to find each other. They exchange a small amount of connection information, such as network addresses. This step is called “signaling”.

Signaling does use a server, but only to pass that short introduction message. Once the connection is set up, the file data travels over the WebRTC channel, not through the signaling server.

Think of it like a mutual friend introducing two people: the friend passes on a phone number, but isn’t on the call and never hears the conversation.

What About Relay Servers?

Most of the time, two devices can connect directly. But some networks, such as strict office, school or hotel Wi-Fi, block direct connections between devices. In those cases WebRTC can fall back to a relay server (known as a TURN server) that passes the data along between the two devices.

This is still very different from cloud storage:

  • The data stays encrypted end to end, so the relay can’t read the file
  • The relay only forwards data in real time; it doesn’t store the file
  • Nothing is left behind once the transfer finishes

If you’re on mobile data or a home network, a direct connection is the usual result.

Is WebRTC Encrypted?

Yes. Encryption is mandatory in WebRTC, not an optional setting. Data channels are protected with DTLS (Datagram Transport Layer Security), the same family of encryption that secures websites using HTTPS. Browsers will not set up an unencrypted WebRTC connection.

This means anyone sitting between the two devices, such as a public Wi-Fi network or an internet provider, sees only scrambled data, not your files.

Why P2P Transfer is More Private

When files are stored on a company’s server:

  • The company holds a copy of your file
  • Their privacy policy decides how long they keep it
  • Their security practices decide how well it’s protected
  • If they suffer a data breach, your files could be exposed

When files move peer-to-peer via WebRTC:

  • No company stores your file
  • Nothing is saved anywhere except on the sender’s and receiver’s devices
  • When the session ends, there’s no stored copy left to leak
  • The service provider cannot see what was transferred

Is WebRTC Fast?

Often, yes. Because there’s no separate upload-then-download step, the file only travels once. On the same Wi-Fi network, two devices can transfer files much faster than uploading to the cloud and downloading again.

Actual speed depends on your Wi-Fi, your devices and the browser. As a rough guide, at 50 Mbps a 1 GB file takes around 3 minutes; on a faster local network it can be quicker. Over the internet, between devices in different places, speed depends on the slower of the two connections.

Where Else is WebRTC Used?

You’ve likely used WebRTC without realising it:

  • Video calls in the browser, such as Google Meet
  • Voice and screen sharing in browser-based chat and meeting apps
  • Browser-to-browser file transfer tools, including BeamQR

The same technology that carries a live video call reliably across the world is what moves your files between your laptop and phone.

Summary

WebRTC lets two browsers connect and exchange data over an encrypted channel. It’s built into every modern browser, so there’s nothing to install. A signaling server introduces the two devices, and on strict networks a relay may forward the encrypted data, but your file is never uploaded to storage or kept by anyone.

The result is a file transfer method that is private by design, avoids the double upload-and-download of cloud services, and needs no account or storage quota.

See WebRTC in action: Try BeamQR File Transfer →