DEV Community

Cover image for How to Use Tunnelmole as a Reverse Proxy: The Open Source Approach
Robbie Cahill
Robbie Cahill

Posted on • Originally published at softwareengineeringstandard.com

How to Use Tunnelmole as a Reverse Proxy: The Open Source Approach

#reverseproxy #opensource #javascript #typescript

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.

How Tunnelmole Works

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
Enter fullscreen mode Exit fullscreen mode

Install via script (Linux/macOS/WSL) 

curl -O http://install.tunnelmole.com/xD345/install && sudo bash install
Enter fullscreen mode Exit fullscreen mode

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'));
Enter fullscreen mode Exit fullscreen mode

Start your app:

node app.js
Enter fullscreen mode Exit fullscreen mode

Now, use Tunnelmole to create a reverse proxy:

tmole 3000
Enter fullscreen mode Exit fullscreen mode

You’ll get output like:

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

http://abc12.tunnelmole.net ⟶ http://localhost:3000
http://abc12.tunnelmole.net ⟶ http://localhost:3000
Enter fullscreen mode Exit fullscreen mode

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)
Enter fullscreen mode Exit fullscreen mode

Start your Flask app:

python app.py
Enter fullscreen mode Exit fullscreen mode

Expose it with Tunnelmole:

tmole 5000
Enter fullscreen mode Exit fullscreen mode

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
Enter fullscreen mode Exit fullscreen mode

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
Enter fullscreen mode Exit fullscreen mode

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

Advanced: Integrating Tunnelmole in Node.js/TypeScript Projects

Tunnelmole can be used programmatically as an npm dependency:

npm install --save tunnelmole
Enter fullscreen mode Exit fullscreen mode

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);
})();
Enter fullscreen mode Exit fullscreen mode

You can also specify a custom domain:

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

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?

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.

Top comments (1)

Collapse
 
nathan_tarbert profile image
Nathan Tarbert •

this is extremely impressive for a walkthrough, especially showing real steps for each stack
you ever hit any snags using it with more complex, multi-service projects