This content originally appeared on DEV Community and was authored by Robbie Cahill

How to Use Tunnelmole as a Reverse Proxy

Reverse proxies are a foundational tool for modern web development, enabling secure, flexible, and scalable access to internal services. Whether you’re exposing a local API for testing, sharing a development site, or integrating with third-party webhooks, a reverse proxy can make your life much easier.

In this guide, you’ll learn how to use Tunnelmole, an open source tunneling tool, as a reverse proxy for your local applications. We’ll cover what a reverse proxy is, why you might need one, and provide hands-on examples for Node.js, Python, and Dockerized services.

What is a Reverse Proxy?

A reverse proxy is a server that sits in front of one or more backend servers and forwards client requests to them. Unlike a traditional (forward) proxy, which routes outbound traffic from clients to the internet, a reverse proxy handles inbound traffic, acting as a gateway between external users and your internal services.

Key benefits of using a reverse proxy:

• Expose local services to the internet without deploying to production
• Secure endpoints with HTTPS, even for local development
• Test webhooks from third-party providers (Shopify, Stripe, GitHub, etc.)
• Share work-in-progress with teammates or clients
• Bypass NAT/firewall restrictions for IoT, mobile, or remote devices

Why Use Tunnelmole as a Reverse Proxy?

Tunnelmole is an open source tunneling tool that makes it easy to create a reverse proxy for any local HTTP or HTTPS service. Unlike some proprietary solutions, Tunnelmole is:

• Open Source: Both client and server are open source, so you can self-host or audit the code.
• Free to Use: Get public URLs for your local services at no cost.
• Custom Subdomains: Use your own subdomain (with a paid plan or self-hosted).
• Self-Hostable: Run your own Tunnelmole server for full control.
• Native Node.js: Easy integration with JavaScript and TypeScript projects.

Tunnelmole is ideal for developers who want a transparent, flexible, and developer-friendly reverse proxy solution.

How Tunnelmole Works as a Reverse Proxy

Tunnelmole creates a secure tunnel from your local machine to a public URL. When someone accesses the public URL, Tunnelmole forwards the request to your local server—acting as a reverse proxy.

Typical workflow:

1. Start your local server (e.g., Node.js on port 3000).
2. Run Tunnelmole to expose that port.
3. Receive a public HTTPS URL that forwards requests to your local server.

Installing Tunnelmole

Tunnelmole supports Linux, macOS, and Windows. You can install it via npm or download a precompiled binary.

Install with npm (requires Node.js 16.10+)

sudo npm install -g tunnelmole

Install via script (Linux/macOS/WSL)

curl -O https://install.tunnelmole.com/xD345/install && sudo bash install

Windows

1. Download tmole.exe
2. Add it to your PATH.

For more details, see the official Tunnelmole installation guide.

Using Tunnelmole as a Reverse Proxy: Step-by-Step

Let’s walk through practical examples of using Tunnelmole as a reverse proxy for different development scenarios.

1. Exposing a Local Node.js App

Suppose you have an Express app running on port 3000:

// app.js
const express = require('express');
const app = express();
app.get('/', (req, res) => res.send('Hello from local Node.js!'));
app.listen(3000, () => console.log('App listening on port 3000'));

Start your app:

node app.js

Now, use Tunnelmole to create a reverse proxy:

tmole 3000

You’ll get output like:

Your Tunnelmole Public URLs are below and are accessible internet wide. Always use HTTPs for the best security

https://abc12.tunnelmole.net ⟶ http://localhost:3000
http://abc12.tunnelmole.net ⟶ http://localhost:3000

Anyone visiting the public URL will be reverse proxied to your local app.

2. Reverse Proxy for a Python Flask App

Let’s say you have a Flask app on port 5000:

# app.py
from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello():
    return "Hello from Flask!"

if __name__ == '__main__':
    app.run(port=5000)

Start your Flask app:

python app.py

Expose it with Tunnelmole:

tmole 5000

Now, your Flask app is accessible via a public reverse proxy URL.

3. Exposing a Dockerized Service

If you’re running a service in Docker, map the container port to your host, then use Tunnelmole:

docker run -p 8080:80 nginx
tmole 8080

Tunnelmole will reverse proxy requests from the public URL to your Nginx container.

4. Using a Custom Subdomain

For a stable, memorable URL, use a custom subdomain (requires a paid plan or self-hosting):

tmole 3000 as myapp.tunnelmole.net

Now, your reverse proxy URL will be https://myapp.tunnelmole.net.

Advanced: Integrating Tunnelmole in Node.js/TypeScript Projects

Tunnelmole can be used programmatically as an npm dependency:

npm install --save tunnelmole

Example usage in a Node.js script:

import { tunnelmole } from 'tunnelmole';

(async () => {
  const url = await tunnelmole({ port: 3000 });
  console.log('Public reverse proxy URL:', url);
})();

You can also specify a custom domain:

const url = await tunnelmole({
  port: 3000,
  domain: 'myapp.tunnelmole.net'
});

Common Use Cases for Reverse Proxy with Tunnelmole

• Webhook Development: Receive webhooks from Stripe, Shopify, GitHub, etc., on your local machine.
• Mobile App Testing: Test APIs from real devices using a public URL.
• Client Demos: Share a work-in-progress site with stakeholders.
• IoT Device Integration: Expose local device endpoints for remote access.
• Bypass Corporate Firewalls: Access local services from anywhere.

Security Considerations

When using a reverse proxy to expose local services, keep these best practices in mind:

• Use HTTPS URLs: Tunnelmole provides HTTPS by default for security.
• Limit Exposure: Only expose ports/services you need.
• Authentication: Add authentication to sensitive endpoints.
• Monitor Usage: Be aware that public URLs are accessible internet-wide.

Self-Hosting Tunnelmole for Full Control

If you need complete control over your reverse proxy setup, you can self-host the Tunnelmole service. This is ideal for:

• Enterprise environments
• Custom domain requirements
• Regulatory compliance

See the Tunnelmole Service GitHub repo for setup instructions.

Frequently Asked Questions

Q: Is Tunnelmole really open source?

A: Yes, both the client and server are open source. You can self-host or use the hosted service.

Q: Does Tunnelmole hide my IP?

A: No, the hosted service adds an X-Forwarded-For header with your IP for transparency. You can self-host and modify this if needed.

Summary

Tunnelmole makes it easy to set up a reverse proxy for any local service, whether you’re building with Node.js, Python, Docker, or other platforms. As an open source, self-hostable, and developer-friendly tool, Tunnelmole is a great choice for anyone needing secure, flexible, and fast reverse proxy access.

Ready to try Tunnelmole as your reverse proxy?

• Get started with Tunnelmole
• View the GitHub repo
• Read the full documentation

Next Steps:

• Install Tunnelmole and expose your first local service
• Try integrating with webhooks or mobile devices

Tunnelmole: The open source reverse proxy for developers.

This content originally appeared on DEV Community and was authored by Robbie Cahill