Universal peer-to-peer connectivity library
End-to-end encrypted messaging across five languages. No infrastructure required to get started.
Why cairn
A single protocol for direct, encrypted communication between peers -- regardless of language or platform.
Five Languages, One Protocol
Rust, TypeScript, Go, Python, and PHP implementations that fully interoperate over the same wire protocol.
Secure by Default
Noise XX handshake with Double Ratchet for forward secrecy. Encryption is always on, not opt-in.
Progressive Infrastructure
Start peer-to-peer with zero servers. Add signaling and relay only when your deployment needs it.
Get started in minutes
Pair two nodes, establish a session, and start sending messages.
- Rust
- TypeScript
- Go
- Python
- PHP
use cairn_p2p::{Node, CairnConfig, create};
let node = create(CairnConfig::default())?;
node.start().await?;
let pairing = node.pair_generate_pin().await?;
println!("PIN: {}", pairing.pin);
// Responder enters PIN, then:
let session = node.connect(&peer_id).await?;
session.send("chat", b"hello").await?;
import { Node } from 'cairn-p2p';
const node = await Node.create();
const { pin } = await node.pairGeneratePin();
console.log(`PIN: ${pin}`);
// Responder enters PIN, then:
const session = await node.connect(peerId);
await session.send('chat', Buffer.from('hello'));
import cairn "github.com/moukrea/cairn/packages/go/cairn-p2p"
node, _ := cairn.Create()
data, _ := node.PairGeneratePin()
fmt.Println("PIN:", data.Pin)
// Responder enters PIN, then:
session, _ := node.Connect(peerId)
session.Send("chat", []byte("hello"))
from cairn import create
node = await create()
data = await node.pair_generate_pin()
print(f"PIN: {data.pin}")
# Responder enters PIN, then:
session = await node.connect(peer_id)
await session.send("chat", b"hello")
use Cairn\Node;
$node = Node::create();
$data = $node->pairGeneratePin();
echo "PIN: " . $data->pin . "\n";
// Responder enters PIN, then:
$session = $node->connect($peerId);
$session->send('chat', 'hello');
Infrastructure tiers
Deploy what you need. Each tier builds on the previous one.
Tier 0
Peer-to-peer only- Setup
- None
- NAT traversal
- Public STUN, best-effort
- Discovery
- 5-30s (DHT/mDNS)
- Offline messages
- No
- Relay
- No
- Multi-device
- Manual
- Cost
- Free
Tier 1
With signaling- Setup
- 2 Docker containers
- NAT traversal
- TURN relay, symmetric NAT
- Discovery
- <1s (signaling)
- Offline messages
- No
- Relay
- Yes
- Multi-device
- Manual
- Cost
- Free (Cloudflare) or ~$5/mo VPS
Tier 2
Full stack- Setup
- 3 Docker containers
- NAT traversal
- Full
- Discovery
- <1s
- Offline messages
- Yes (store-and-forward)
- Relay
- Yes
- Multi-device
- Automatic (hub)
- Cost
- Same + storage