Test Locally Hosted Websites With Selenium

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TestMu AI Tunnel creates a secure, encrypted connection between your local machine and the TestMu AI cloud grid. Use it to test web apps running on localhost, staging servers, or behind a firewall without exposing them to the internet. The tunnel uses TCP with TLS 1.2 over port 443 or WebSocket.

How It Works

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The tunnel binary runs on your machine and establishes an encrypted connection to the TestMu AI cloud. When you set tunnel: true in your test capabilities, the cloud browser routes traffic through this connection to reach your local app.

Your Machine (localhost:3000) <-- Encrypted Tunnel --> TestMu AI Grid <--> Cloud Browser

Step 1: Download the Tunnel Binary

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Download the binary for your operating system and architecture.

Platform	Download Link
Windows (AMD64)	https://downloads.lambdatest.com/tunnel/v3/windows/amd64/LT.exe
macOS (AMD64)	https://downloads.lambdatest.com/tunnel/v3/mac/amd64/LT
macOS (ARM64 / Apple Silicon)	https://downloads.lambdatest.com/tunnel/v3/mac/arm64/LT
Linux (AMD64)	https://downloads.lambdatest.com/tunnel/v3/linux/amd64/LT
Linux (ARM64)	https://downloads.lambdatest.com/tunnel/v3/linux/arm64/LT

For the full list of platform binaries, see the TestMu AI Tunnel documentation.

After downloading, make the binary executable (macOS/Linux):

chmod +x LT

Step 2: Start the Tunnel

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Open a terminal, navigate to the folder with the binary, and start the tunnel with your credentials.

LT --user undefined --key undefined

You should see a message confirming the tunnel is active. Keep this terminal open while running your tests.

Named tunnels

Run multiple tunnels by giving each a name:

LT --user YOUR_USERNAME --key YOUR_ACCESS_KEY --tunnelName my-staging-tunnel

Then reference it in your capabilities with "tunnelName": "my-staging-tunnel".

Step 3: Add the Tunnel Capability to Your Tests

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Set tunnel: true in your test capabilities. Here is how to do it in each language.

Java

ChromeOptions browserOptions = new ChromeOptions();
browserOptions.setPlatformName("Windows 10");
browserOptions.setBrowserVersion("latest");

HashMap<String, Object> ltOptions = new HashMap<String, Object>();
ltOptions.put("build", "Local Test Build");
ltOptions.put("name", "Local Test");
ltOptions.put("tunnel", true);       // Enable tunnel
ltOptions.put("w3c", true);
browserOptions.setCapability("LT:Options", ltOptions);

JavaScript

const capabilities = {
  browserName: 'Chrome',
  browserVersion: 'latest',
  'LT:Options': {
    platformName: 'Windows 10',
    build: 'Local Test Build',
    name: 'Local Test',
    tunnel: true,       // Enable tunnel
    w3c: true,
  }
};

Python

lt_options = {
    "build": "Local Test Build",
    "name": "Local Test",
    "tunnel": True,       # Enable tunnel
    "w3c": True,
}
options.set_capability("LT:Options", lt_options)

C#

var ltOptions = new Dictionary<string, object>
{
    { "build", "Local Test Build" },
    { "name", "Local Test" },
    { "tunnel", true },       // Enable tunnel
    { "w3c", true }
};
browserOptions.AddAdditionalOption("LT:Options", ltOptions);

PHP

$capabilities = [
    "browserName" => "Chrome",
    "browserVersion" => "latest",
    "LT:Options" => [
        "platformName" => "Windows 10",
        "build" => "Local Test Build",
        "name" => "Local Test",
        "tunnel" => true,       // Enable tunnel
        "w3c" => true,
    ]
];

Ruby

options = Selenium::WebDriver::Options.chrome(
  platform_name: "Windows 10",
  browser_version: "latest",
  "LT:Options": {
    build: "Local Test Build",
    name: "Local Test",
    tunnel: true,       # Enable tunnel
    w3c: true,
  }
)

If you are using a named tunnel, add "tunnelName": "my-staging-tunnel" to the LT:Options as well.

Step 4: Point Your Test to localhost

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Use localhost or your internal URL in driver.get(). The tunnel routes the request from the cloud browser to your local machine.

// This works because the tunnel is active
driver.get("http://localhost:3000");

Common Issues

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Quick fixes for problems you might hit with local testing.

Problem	Solution
Tunnel won't start	Check that your username and access key are correct. Ensure no firewall is blocking outbound connections over port 443.
Page loads but shows "connection refused"	Verify your local app is running on the port you specified. Check that the app binds to 0.0.0.0, not just 127.0.0.1.
Tests timeout on local URLs	Increase the idle timeout capability: "idleTimeout": 300. Local apps may respond slower through the tunnel.
Multiple tunnels conflicting	Use named tunnels with --tunnelName and reference the name in capabilities with "tunnelName".
SSL certificate errors on localhost	Start the tunnel with --mitm flag to test sites with self-signed certificates on your local machine or internal network.

note

For YAML-based configuration, verbose logging, Info APIs, MITM mode, and all advanced options, see the TestMu AI Tunnel documentation and TestMu AI Tunnel Features.