Opera Dragonfly documentation

Remote Debugging

The Remote Debug feature allows Opera Dragonfly to connect to other instances of Opera, either on the same machine or on a remote device. This is especially useful when working with devices such as mobile phones, tablets, and TVs. When put into Remote Debugging mode, Opera Dragonfly will listen for a connection to the IP address and Port specified. The separate instance of the Opera browser can then connect over a network and pass debugging information across the connection. Opera Dragonfly can then interact with the webpages and applications on the remote instance, just as if it were running locally.


The following steps create the setup for a remote debugging session.

Stage 1: Network setup

The first step is to make sure both instances are connected to the same network, so they can "see" each other. If debugging a mobile device, it will be useful to connect to a Wi-Fi network. To establish a connection, you will need to point the instance of Opera you want to debug (the client) to the instance of Opera Dragonfly (the server). For this, you'll need to make a note of the IP address of the machine running Opera Dragonfly.

If connecting to a separate instance on the same machine, such as a different version of the Opera browser or the Opera Mobile Emulator, it is possible to simply use (localhost).

Finding the IP Address in OS X using Network preferences and ifconfig in the terminal

In OS X, the quickest way to find the IP address of your machine is to go to the system's Network preferences. Similarly, Linux will generally provide a Connection Information dialog relating to the currently active network connections.

In both OS X and Linux it is also possible to go the command-line route. Enter ifconfig in a terminal window and look for the inet value of the active connection. If there are multiple active network connections – such as Ethernet, Wi-Fi, Bluetooth, or others – there will be multiple inet values, so it is important to make sure you're checking the right connection.

Finding the IP Address in Windows, using the Command Prompt and ipconfig

On Windows, there is no easy method to check the current IP address from the system settings. However, opening a Command prompt and entering ipconfig will yield a similar result to ifconfig on OS X and Linux.

Stage 2: Listen for a connection

To begin debugging remotely In Opera Dragonfly perform the following steps:

  1. Click the Remote Debug button at the top-right of the Opera Dragonfly window.
  2. Specify the port that will be used to connect over. This defaults to 7001. Make sure the firewall is configured to allow connections on the chosen port.
  3. Click the Apply button.

Set the port and listen for a connection

Stage 3: Connect to Opera Dragonfly

On the remote Opera instance, perform the following steps:

  1. Enter opera:debug in the URL field.
  2. Enter the IP address and port number from stage 1.
  3. Click Connect.

Enter the IP Address and port on the remote device

If the connection is successful, Opera Dragonfly will communicate with the remote instance and will be ready to debug the selected document. The Remote Debug button will light up to show the connection is established. If the connection drops for whatever reason, it will switch to an error indicator.

Debugging pages on a remote device

With the connection established, the final step is to select the document to debug. The debugging context selector at the upper-right of the Opera Dragonfly window contains a list of the open documents on the remote device. Navigate to the page to be debugged on the remote device and make sure the correct document is selected in the document selector. It may also be useful to detach Opera Dragonfly to provide more visual real estate.

Selecting the debugging context

Everything will behave as if a local document is being debugged. The main difference is that the page being debugged is controlled and displayed on the remote device. Changes made to the DOM or styles can still be made in real time. There may. however, be some delay depending on the latency of the connection and the performance of the device.


Once the debugging session is over, the remote debugging connection can be disconnected by clicking on the Remote Debug button, and then clicking on the Cancel button. It can also be disconnected on the device by returning to opera:debug and clicking the Disconnect button. Opera Dragonfly will then return to local debug mode.