James Bachini

Spying on Mobile Ads from Firefox

If you want to know what ads are running on a mobile site anywhere in the world you can do this with Firefox without going anywhere near a mobile device. Simply download the following add-ons:

  • User Agent Switcher
  • Modify Headers

Simply select the device you want to “look through” in User agent switcher and then grab a http user agent and paste it into Modify headers. User agents can be found quite simply using google it is just a line of text.


It’ll look something like this:

Mozilla/5.0 (iPhone; U; XXXXX like Mac OS X; en) AppleWebKit/420+ (KHTML, like Gecko) Version/3.0 Mobile/241 Safari/419.3

Load up whatever site you want to view and it will pop up with the mobile version of that site along with any ads being displayed.

You can take this to the next level with Overplay VPN and see ads from anywhere in the world.


NB. You can use the same software to check if someone is cloaking on google for example by posing as a googlebot.


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James Bachini

Disclaimer: Not a financial advisor, not financial advice. The content I create is to document my journey and for educational and entertainment purposes only. It is not under any circumstances investment advice. I am not an investment or trading professional and am learning myself while still making plenty of mistakes along the way. Any code published is experimental and not production ready to be used for financial transactions. Do your own research and do not play with funds you do not want to lose.