Do you know how much the browser knows about you?

The browser knows much more about you than you imagine.

As a web developer, lately I am receiving many questions about the “data we share on the Internet”. And although it is true that we must be careful with what is shared on the Internet, I also tell them that it is impossible to have absolute control over what the websites can know about us.

In short, the browser with which you move through the different Internet pages can get to know (without having to ask for your consent) your location, what operating system you use, the features of your computer, how you connect to the Internet and much more. You do not believe me? Try it for yourself.

Now that you know the truth there is no turning back. It’s no use trying to erase your digital fingerprint.

Although it is hard to believe, what you have seen is part of the information (not all) that your browser can access without even asking permission to do so. Robin Linus developed the page previusly mentioned precisely for the purpose of letting everyone know what a page is capable of without the user’s consent.

Fortunately, there are certain precautions we can take to minimize the information we expose.

Let’s analyze all this in detail before our head explodes

Let’s see point by point of what data we are talking about.


There are times when certain pages ask us to give them access to our location. Why will this page want to know where we are? Very simple, all the data we generate is worth.

The thing is that even if we reject the request, the Google API can give us a rough idea of our location, which, although not entirely accurate, is something to worry about. The margin of error can be approximately 50 km, enough for the navigator to know in what area of the world we move.

Within the scope of ‘Location’ are included geographical coordinates, postal address, local language and time.


For those of you who are already a bit involved in the computer world, no explanation is necessary. For the rest, when we talk about software, we talk about the browser can get to know:

  • The operating system of your computer (if we use MacOS, Windows, Linux or any other system — such as mobile systems).
  • The browser version.

The bad thing about the browser knowing what software we use is that if this information falls into the hands of someone who wants to do us wrong, to make a computer attack, for example, this information is very useful because it could make use of vulnerabilities detected in the version of our software.

Recommendation: always have the software updated. Using old versions of software is nothing more than an open door to anyone with inappropriate intentions.


The hardware, in a simplified way, is the physical. What you see on your computer, be it a mobile phone or a tablet or computer (CPU, GPU, etc.).

We see that the browser is able to know the number of cores of our CPU, the graphics card that we use together with the screen resolution, and information about the battery.

As happens with the software, if any of our parts have any flaw or vulnerability, we are screwed up. Correcting a hardware failure is more difficult and expensive.

Social networks

Surely this you did not expect but anyone who knows how to access the information that your browser handles can know which social networks you move through. Are you ‘logged in’ on Twitter or Facebook while browsing? In Dropbox? On Netflix? Your browser knows it, and with it, the websites you visit.

In principle, that they know in what social networks you are moving does not have much danger, but it never hurts to know that they can know it.


The IP is what identifies us on the Internet and anyone can know our IP address without too much effort. That is why many people try to hide it using VPNs. Privacy is increased with a Virtual Private Network because the user’s initial IP address is replaced with one from the Virtual Private Network provider. Subscribers can obtain an IP address from any gateway city the VPN service provides. For instance, you may live in San Francisco, but with a Virtual Private Network, you can appear to live in Amsterdam, New York, or any number of gateway cities.

As an addition, it is also public which our ISP is, that is, the company that provides us with Internet, and even the download speed that we have.

No need to go to those pages with speedometers to know if the 30 megs you hired are real. Anyone can know your speed!

Analysis of the network

If we click on the button and wait a while, we see that several IP addresses start to appear. These are the IPs we are using. In short, you can know how many computers are connected right now in your network, and it is possible to use this for better or for worse. It always depends on the person who handles this data…


Finally there are the images. Yes, the images. Now how fashionable are uploading them to social networks to ‘show others the great lives we have’.

The images, and the rest of the files, contain metadata. Metadata is data about other data. That is, if an image is a piece of information, its metadata are its resolution, its weight, and even the camera model that has been used to take it. Not always this information is housed within the images but most of the time yes. Sometimes, there is data about the place where the photo was taken. Although it is hard to believe, this has been used to solve crimes. Here is an online tool to discover what an image that you have taken knows.

As you can see, you can know the date and time the photograph was taken, the software that was used to edit it and even if it was taken with flash. All this is saved in a photo as soon as we press the button. There are online tools that allow you to delete the metadata, in case all this worries you.

What can you do to prevent all this?

To finish, here are some things you can do to avoid all this information being accessible, although of course they will make your navigation more uncomfortable. There is always light at the end of the tunnel! Here are some tips:

  • Delete the ‘cookies’ and the browsing history periodically. These files are installed in the browser to ‘follow’ you online and make the experience easier and more comfortable, and for that they accumulate a lot of information about you.
  • Use a proxy, a server that acts as an intermediary in the requests you make to the Internet, so that the server that returns them does not really know where you are, what device you are using, or much of the aforementioned information.
  • You can also use NoScript, an extension for Mozilla Firefox and other browsers. This blocks the execution of Javascript, Java, Flash and other add-ons except on websites that you indicate as secure.

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