A drop-in SDK that lets browsers talk to local daemons reliably – no reconnect logic, no NAT hacks, no exposed ports. E2EE by default.
Reconnects, multiplexing, and correlation are handled for you. Delete your WebSocket code. Focus on your app.
Works behind NAT, firewalls, and mobile networks. No port forwarding. No VPNs. No tunnels.
End-to-end encrypted by default. The relay never sees your data. Ed25519 · X25519 · ChaCha20.
Stop maintaining connection state machines. Sideband handles reconnects, multiplexing, and NAT traversal so you can focus on your app.
// Connection state machine
let ws: WebSocket | null = null;
let reconnectAttempts = 0;
const pendingMessages: Message[] = [];
function connect() {
ws = new WebSocket(url);
ws.onopen = () => {
reconnectAttempts = 0;
flushPendingMessages();
};
ws.onclose = (e) => {
if (e.code !== 1000) {
const delay = Math.min(
1000 * 2 ** reconnectAttempts, 30000
);
setTimeout(connect, delay + Math.random() * 1000);
reconnectAttempts++;
}
};
ws.onmessage = (e) => {
const msg = JSON.parse(e.data);
// Correlation, routing, error handling...
};
}
// + CORS, heartbeats, message buffering...
import { createPeer } from "@sideband/peer";
const peer = createPeer({
relay: "wss://relay.sideband.cloud"
});
// Reconnects, NAT traversal, E2EE - handled.
const response = await peer.request("daemon", {
method: "getStatus"
});
Compare with common alternatives for browser-to-daemon communication.
| Sideband | DIY WebSocket | ngrok | Tailscale | Firebase | |
|---|---|---|---|---|---|
| No WebSocket code | — | ||||
| Works behind NAT | — | ||||
| End-to-end encrypted | — | — | — | ||
| No interstitial pages | — | ||||
| No account required | — | — | — | ||
| Self-hostable relay | — | — | |||
| TypeScript SDK | — | — | — |
Sideband is designed for developers building tools that need reliable browser-to-daemon communication.
Give your AI agent a browser UI without exposing localhost or managing WebSocket state machines.
Build CLI companions, dashboard GUIs, and debugging interfaces that work across any network.
Keep data on the user's machine while providing a polished browser experience from anywhere.
Get started in minutes with the Sideband SDK.