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.

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, you have hostc.
• 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 every open device the moment you save. Server-Sent Events stream as they are produced.
• Dev servers accept it as is. Requests arrive addressed to localhost and redirects point back to the public URL, so there is no allowed-hosts setting to change.
• The link survives. Network drops and server restarts don't change the URL; hostc reconnects on its own.
• Free and open source. The server is a Cloudflare Worker you can also run on your own domain.

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,
• let a coding agent share what it built. Point the agent at hostc.dev/llms.txt and it knows how to run hostc and read the URL.

Usage

hostc <target> [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
  -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.

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

Always run @latest

hostc is free and moves fast, so server updates can be incompatible with older CLIs. Run it with npx hostc@latest and you always get the matching version.

Don't install it globally (npm i -g hostc) or add it to a project: an installed copy stays on its version and stops working when the server moves on. An outdated CLI stops at startup and tells you to upgrade.

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

1. Add your domains to Cloudflare: one for the API and one for tunnels, for example example.com and example.app. They can be the same domain, but a separate tunnel domain keeps tunnel cookies and abuse reports away from your main site. Add a proxied wildcard DNS record on the tunnel domain (* → 192.0.2.1); Cloudflare's Universal SSL covers *.example.app.

2. Set the token secret once: pnpm -F @hostc/server exec wrangler secret put TOKEN_SECRET --name hostc-tunnel (at least 32 random bytes, e.g. openssl rand -base64 48).

3. Deploy:

   API_DOMAIN=example.com TUNNEL_DOMAIN=example.app pnpm deploy:server

4. Use it: npx hostc@latest 3000 --server https://example.com, or build the CLI with HOSTC_DEFAULT_SERVER=https://example.com pnpm build.

Contributing

Requires Node.js 22.22+ and pnpm.

pnpm install
cp apps/server/.env.example apps/server/.env
pnpm dev                       # tunnel server on http://localhost:8787
pnpm build                     # build the CLI
node apps/cli/dist/hostc.mjs 3000 --server http://localhost:8787

Tunnels are served on http://<id>.localhost:8787; Chrome and Firefox resolve *.localhost to your machine.

pnpm check      # format check, lint, typecheck, unit and integration tests
pnpm test:e2e   # wrangler dev + CLI + a local origin, end to end

Path	What
packages/protocol	frame format, messages and constants shared by both sides
packages/client	Node.js client: connection, streams, reconnects
apps/server	Cloudflare Worker + Durable Object tunnel server
apps/cli	the hostc command
apps/web	hostc.dev website (one static page) and llms.txt

Issues and pull requests are welcome.

If hostc is useful to you, star it on GitHub.

License

Apache-2.0