# offline-browser-communication

**Repository Path**: mirrors_pion/offline-browser-communication

## Basic Information

- **Project Name**: offline-browser-communication
- **Description**: Demonstration of a browser connecting to Pion WebRTC without a signaling server.
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-09-25
- **Last Updated**: 2025-12-28

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

The techniques shown in this repo no longer work. Chrome disabled the modification of the ICE ufrag/pwd. You can see the announcement [here](https://groups.google.com/g/discuss-webrtc/c/PIJZN5MTZF4/m/JHVmmn8yDgAJ?pli=1)

Allowing two peers to connect in a LAN without having to hit a signaling server is something I am still interested in. I hope to come back to this topic someday. If you are interested please contact me
and would love to make this an offical web api!

------

<h1 align="center">
  <a href="https://pion.ly"><img src="./.github/pion-gopher-webrtc.png" alt="Pion WebRTC" height="250px"></a>
  <br>
  Offline Browser Sync
  <br>
</h1>
<h4 align="center">WebRTC without a signaling server!</h4>
<p align="center">
  <a href="https://pion.ly"><img src="https://img.shields.io/badge/pion-webrtc-gray.svg?longCache=true&colorB=brightgreen" alt="Pion webrtc"></a>
  <a href="https://pion.ly/slack"><img src="https://img.shields.io/badge/join-us%20on%20slack-gray.svg?longCache=true&logo=slack&colorB=brightgreen" alt="Slack Widget"></a>
  <br>
  <a href="LICENSE"><img src="https://img.shields.io/badge/License-MIT-yellow.svg" alt="License: MIT"></a>
</p>
<br>

This repo demonstrates how you can connect two WebRTC proccesses without signaling. No configuration is needed ahead of time, so no hardcoding of IP Addresses.
The peers use mDNS to connect to each other, and have pre-set ICE Credentials and DTLS Certificates.

### Running
* `git clone https://github.com/pion/offline-browser-communication.git`
* `cd offline-browser-communication`
* `go run *.go`
* Open https://jsfiddle.net/nah7qvkj/

You should see the following in your terminal.
```
Ready to connect, please load https://jsfiddle.net/nah7qvkj/
Connection State has changed checking
Connection State has changed connected
DataChannel foo has opened
```

If everything worked you can now send messages from your browser to your terminal!

### What this means
This means you can have two devices connect without any setup. No need to setup a server, or native apps with more control.

You could build stuff like.
* Sync data between two PWA without a backend
* Have a multiplayer game that never leaves your network
* Build a conferencing/chat app that doesn't require any setup
* *Please share your cool ideas with us!*

### FAQ
#### Is this secure?

No currently everything is hardcoded, this is just a demonstration. I believe this could be reasonably secure if seeded properly. Better to ask a security person though.

#### What platforms are supported?

OSX and Linux

#### What browsers work?

Only Chromium so far. If there is interest I would like to support more

#### What libraries/dependencies does this use

Only [Pion WebRTC](https://github.com/pion/webrtc) it is a full Go implementation of WebRTC. It has zero C/C++ usage.

#### What is next?

I would like to get this into the IETF/W3C, but as an individual I am unable to be involved. If you are interested and have membership please reach out!

#### I want to talk about cool WebRTC stuff!

Join the [Pion Slack](https://pion.ly/slack)

#### I need to update the DTLS Fingerprint
If you see an error like `InvalidAccessError: x509Cert expired` the certificate has expired. You can update it by following these instructions. Please submit a PR
with the updated certificate as well, thanks!

```
  // Create new certificate
  go run `go env GOROOT`/src/crypto/tls/generate_cert.go --host=localhost --ecdsa-curve=P256

  // Create new fingerprint for jsfiddle
  openssl x509 -noout -fingerprint -sha256 -inform pem -in cert.pem
```

### Community
Pion has an active community on the [Golang Slack](https://invite.slack.golangbridge.org/). Sign up and join the **#pion** channel for discussions and support. You can also use [Pion mailing list](https://groups.google.com/forum/#!forum/pion).

We are always looking to support **your projects**. Please reach out if you have something to build!

If you need commercial support or don't want to use public methods you can contact us at [team@pion.ly](mailto:team@pion.ly)

### License
MIT License - see [LICENSE](LICENSE) for full text