Expose – Pure Go Localhost Tunneling CLI

Turn your localhost into a public shareable URL in one command — zero config, zero signups, and a single <10MB binary.
The lightweight, open-source Go alternative to ngrok for webhook testing, mobile previews, and remote debugging.

Install via Homebrew:

brew install kernelshard/tap/expose

Tunnel your local server (e.g. port 3000):

expose tunnel 3000

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💡 What is this for?

When you run an app on http://localhost:3000, only your laptop can access it. Expose creates a temporary public HTTPS URL that connects directly to your local server:

• 🪝 Webhook Testing: Give Stripe, GitHub, or Twilio a live HTTPS URL to test webhook callbacks locally.
• 📱 Mobile & Device Testing: Open your local website on a physical smartphone or tablet over 4G/5G.
• 👥 Instant Previews: Send a live demo link to a friend or client without deploying to cloud servers.
• 🏠 Private Self-Hosting: Route traffic through your own private VPS instead of commercial SaaS relays.

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🆚 Why Expose?

Feature	🚀 Expose	ngrok	Cloudflare Tunnel	LocalTunnel (Node)
Zero Signup Required	✅ Instant	❌ Mandatory account	❌ Mandatory account	✅ Instant
Single Static Binary	✅ (<10MB)	✅ (~30MB)	✅ (~50MB)	❌ (requires Node.js)
Open Source	✅ Apache 2.0	❌ Proprietary	✅ Apache 2.0	✅ MIT
Self-Hostable Relay	✅ expose server	❌ SaaS only	❌ Cloudflare network	⚠️ Legacy Node server
Language & Runtime	Pure Go (zero CGO)	Go / C	Go daemon	Node.js (V8 heap)
Free Custom Domains	🚧 Planned (#62)	💲 Paid plan	✅ Cloudflare DNS	❌ Not supported

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⚡ Quick Examples

# Tunnel a local development server (defaults to port 3000)
expose tunnel 3000

# Tunnel via Cloudflare Quick Tunnels
expose tunnel -P cloudflare -p 8080

# Connect to your private self-hosted relay gateway
expose tunnel 3000 --server=tunnel.mysite.com:7890

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📦 Installation Options

1. Homebrew (macOS & Linux — Recommended)

brew install kernelshard/tap/expose

2. One-Line Shell Installer

curl -fsSL https://raw.githubusercontent.com/kernelshard/expose/main/install.sh | sh

Pin a specific version or install to a custom path:

# Pin version
VERSION=v0.5.1 curl -fsSL https://raw.githubusercontent.com/kernelshard/expose/main/install.sh | sh

# Custom directory
BINDIR=~/.local/bin curl -fsSL https://raw.githubusercontent.com/kernelshard/expose/main/install.sh | sh

3. Pre-built Binaries

Download the latest pre-compiled binary for your architecture (macOS, Linux, Windows) from the Releases Page.

4. Via Go Install (Go 1.22+)

go install github.com/kernelshard/expose/cmd/expose@latest

5. From Source

git clone https://github.com/kernelshard/expose.git
cd expose
go build -o expose ./cmd/expose
./expose --version

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🏠 Self-Hosted Relay Server

Need complete privacy and zero third-party relay dependence? Run your own tunnel gateway on any $5 VPS with a single command:

# Start your private relay server
expose server --domain=tunnel.mysite.com --control-port=7890 --public-port=8080

Connect your client to your VPS (supports custom subdomains):

expose tunnel 3000 --server=tunnel.mysite.com:7890 --subdomain=my-app

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⚙️ Project Configuration (.expose.yml)

Save defaults per project so you can just type expose tunnel:

# Create .expose.yml in current directory
$ expose init
✓ Config created: .expose.yml

project: expose
port: 3000

Manage and query configuration values:

expose config list
expose config get port

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🏗 Architecture & Design Principles

expose/
├── cmd/expose/       # CLI entry point (Cobra)
├── internal/
│   ├── cli/          # Cobra subcommands & flag parsing
│   ├── config/       # YAML config management
│   ├── provider/     # Tunnel providers (LocalTunnel, Cloudflare, Self-Hosted)
│   ├── server/       # Self-hosted relay control & public server
│   ├── tunnel/       # Core service orchestration & lifecycle
│   └── version/      # Build metadata & version injection
└── .expose.yml       # Local project configuration

• Interface-Driven: Extensible Provider interface makes adding new tunnel backends straightforward.
• Clean Separation: CLI → Service → Provider (strict unidirectionality, zero circular dependencies).
• Fully Testable: High test coverage (>80%) across packages with race detector validation (go test -race).

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🧪 Development & Testing

# Run all unit tests with Go race detector
go test ./... -v -race -cover

# Package-specific coverage
go test ./internal/tunnel -cover
go test ./internal/server -cover
go test ./internal/provider -cover

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🤝 Contributing

Contributions are welcome! Please check out CONTRIBUTING.md for branch strategy, test requirements, and code style guidelines.

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📝 License

Distributed under the Apache License 2.0. See LICENSE for details.

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Made with ❤️ by @kernelshard