# Web Debugger

> Inspect HTTP requests and responses in real time. Modify and replay traffic to debug web applications with Pinggy Web Debugger
> Source: https://pinggy.io/docs/http_tunnels/web_debugger/


# Web Debugger

## Overview

The **Web Debugger** lets you inspect HTTP requests and responses flowing through your tunnel in real time. You can watch live traffic, view headers and payloads, and modify and replay requests to debug web applications or APIs hosted on localhost.

The easiest way to use it is straight from the Pinggy dashboard in your browser. There is nothing to install or configure, and it works for free tunnels too (you just need a [free token](https://dashboard.pinggy.io)).

## Web Debugger from the Dashboard

1. **Start a tunnel** with your token. Any HTTP/HTTPS tunnel started with a token shows up in the dashboard.

2. **Open the [Active Tunnels](https://dashboard.pinggy.io/activetunnels) page.** Each running tunnel is listed with its URLs and token. Click the **debug** icon on the row for the tunnel you want to inspect.

   ![Active Tunnels page in the Pinggy dashboard with the debug icon highlighted.](/doc_img/webdebugger/webdebugger_1.png)


3. **Inspect live traffic.** The Web Debugger opens with the tunnel's URLs, connection stats (total connections, requests, responses, bytes transferred), and a live list of requests. Click any request to see its full headers and body, and switch between the **Request** and **Response** tabs.

   ![Web Debugger in the dashboard showing live requests, connection stats, and the request/response panel.](/doc_img/webdebugger/webdebugger_2.png)


4. **Replay or modify requests.** Use **Replay** to re-send a request as-is, or **Modify and Replay** to change the method, path, HTTP version, and any headers before sending it again. This is handy for reproducing a bug or testing how your app handles a tweaked request.

   ![Replay with Modifications dialog showing editable method, path, HTTP version, and headers.](/doc_img/webdebugger/webdebugger_3.png)


## Running the Web Debugger on a Local Port

You can also run the Web Debugger locally instead of using the dashboard. Forward a local port to the debugger when you start the tunnel and open it in your browser. This works without signing in.

1. **Start a tunnel with the Web Debugger port.** Add `-L4300:localhost:4300` to forward the debugger to local port `4300`:

   ```bash
   ssh -p 443 -R0:localhost:8080 -L4300:localhost:4300 free.pinggy.io
   ```

   You can map it to a different local port if `4300` is taken, e.g. `-L9999:localhost:4300` makes the debugger available on port `9999`.

2. **Open the debugger** at `http://localhost:4300` to see live request and response data.

3. **Using the Pinggy CLI** instead of `ssh`:

   ```bash
   ./pinggy -p 443 -R0:localhost:8080 -L4300:localhost:4300 free.pinggy.io
   ```

4. **Programmatic access with APIs.** Retrieve tunnel URLs by sending a GET request to `http://localhost:4300/urls`. Example response:

   ```json
   {
     "urls": [
       "http://rnckk-23.4.5.6.run.pinggy-free.link",
       "https://rnckk-23.4.5.6.run.pinggy-free.link"
     ]
   }
   ```

   To get the list of whitelisted IP addresses, send a GET request to `http://localhost:4300/ipwhitelist`.

## Features

- **Live Request Inspection**: View incoming HTTP requests, including headers, methods, and payloads.
- **Response Monitoring**: Inspect server responses, including status codes and response headers.
- **Modification and Replay**: Modify HTTP requests, including all headers, and replay them to debug your applications.
- **Browser and Local Access**: Use the debugger from the dashboard or run it on a local port.
- **Zero Trust Mode**: If you do not want Pinggy to read your data, then use [TLS tunnels](/docs/tls_tunnels/)
. This will create end-to-end encrypted connections from the browser to your local HTTPS servers. Pinggy or any other actor cannot read your data, maintaining privacy.