hostc

Localhost, anywhere.

One command gives your dev server a public HTTPS URL. WebSockets and hot reload included.
Free, open source, no account.

hostc.dev · 简体中文

Quick start

Start your app, then point hostc at its port:

npx hostc@latest 3000

https://k7m2xq9pa4dn.hostc.app  → http://localhost:3000
Anyone with this URL can reach your local server. Press Ctrl+C to stop.

Open the URL on any device. Every request shows up in your terminal as it arrives. Needs Node.js 22.1 or later.

The URL is public: anyone who has it reaches your server, so only expose what you mean to share.

hostc is free and open source. If it helps you, a star on GitHub helps other developers find it, and it's the best encouragement for the project.

Why hostc

• Nothing to set up. No sign-up, no auth token, no binary to download. If you have Node.js,

• Visitors see your app. No warning page to click through before they reach it.
• Hot reload works. WebSockets pass straight through, so Vite, Next.js and friends update

• Dev servers accept it as is. Requests arrive addressed to localhost and redirects point back

• The link survives. After a network drop or a server restart, hostc reconnects on its own and

Use it to

• share something you built with an AI coding tool before you deploy it anywhere,
• show work in progress to a teammate or a client,
• test webhooks from Stripe, GitHub or Slack against the code on your machine,
• try your site on a real phone, with hot reload (--qr prints a QR code to scan),
• let a coding agent share what it built. Point the agent at

Usage

hostc <target> [options]
hostc codex [options]
3000                     http://localhost:3000
  127.0.0.1:8080           http://127.0.0.1:8080
  https://localhost:5173   any http(s) origin
--server <url>   tunnel server (env HOSTC_SERVER)
  --qr             print a QR code of the public URL
  --here           hostc codex: show only this directory (commands still reach
                   the whole machine)
  -h, --help       show this help
  -v, --version    show the version

Press Ctrl+C to stop; the URL is released immediately. Restarting hostc gives a new URL.

Limits

• 256 requests and WebSockets at once per tunnel. Up to 1024 more wait for a free one; beyond

• WebSocket messages up to 1 MiB. A stream also closes if your local server stops reading and over

• Your local server has 2 minutes to start responding to a request.

Always run @latest

Server updates can be incompatible with older CLIs, so run npx hostc@latest to always get the matching version. Don't install hostc globally (npm i -g hostc) or add it to a project: an installed copy stays on its version, and an outdated CLI stops at startup and tells you to upgrade.

Troubleshooting

What visitors see when a request can't reach your app:

| Error | Meaning | What to do | | ------------------------------ | ---------------------------------------------------- | -------------------------------------------------- | | 404 Tunnel not found | The tunnel was stopped or has expired | Run hostc again for a new URL | | 502 Tunnel offline | hostc isn't connected, usually while it reconnects | Try again in a moment; check that hostc is running | | 502 Local server unavailable | The tunnel is up but your local server didn't answer | Check that it's running on the port you gave hostc | | 503 Tunnel busy | Too many requests at once | Try again in a moment | | 504 Local server timed out | No response started within 2 minutes | Check what your local server is stuck on |

hostc codex (experimental)

Use the Codex CLI on your machine from any browser, including your phone:

npx hostc@latest codex --qr

This is experimental, and it depends on a Codex protocol that is also marked experimental. Read this first:

• The link controls your machine. Anyone who has it can read any file and run any command as

• Asking for approval doesn't protect you from a leaked link. New threads ask before acting, but

• The link lasts until you stop it. The token is random, kept in memory, and replaced on every

hostc is open source, so you can also host it yourself and use --server.

hostc vs Cloudflare Tunnel

hostc runs on Cloudflare too. It does one narrower job than Cloudflare's own tunnels: sharing a dev server for a while.

| | hostc | Quick Tunnel | Cloudflare Tunnel | | ------------------ | -------------------- | ------------------------- | ----------------- | | Install | Node.js only | cloudflared | cloudflared | | Account | None | None | Required | | URL | Random | Random | Your hostname | | Server-Sent Events | Yes | No | Yes | | Dev servers | Work as is | May need the host allowed | Configurable | | Access control | None | Email allowlist | Cloudflare Access | | Made for | Sharing a dev server | Quick tests | Production |

How it works

browser ──▶ Worker ──▶ Durable Object (one per tunnel) ◀── WebSocket ── hostc ──▶ localhost

hostc opens a single outgoing WebSocket, so nothing on your machine has to be reachable from the internet. Each public request or WebSocket becomes a stream on that connection, with flow control for bodies. Idle tunnels sleep on the server, which is what keeps hostc free. The wire format is in docs/protocol.md.

Self-hosting

The server is a Cloudflare Worker you can run on your own domain, then point the CLI at it with --server. See docs/self-hosting.md.

Contributing

Issues and pull requests are welcome. See CONTRIBUTING.md.

License

Apache-2.0