Everyone knows your location, Part 2: try it yourself and share the results

Summary

It's been more than 2 months now since my first post on the topic of location data sharing between various 3rd parties came out – in case you haven't seen it, you should definitely start from there: Everyone knows your locationHow I tracked myself down using leaked location data in the in-app ads, and what I found along the way.Since then I had a chat with a lot of people working in this field – both members of non-profit organisations, fighting for data privacy rights in various countries, and employees of adtech companies, proving my words right or wrong (but mostly right). I was even invited to "Lock and Code" podcast to talk about geolocation data and privacy. Ok, enough with the bragging. I went through the process described in my initial post and decided to make it faster and more scalable: manually going through hundreds of requests in Charles was very cool for research and educational purposes, but it also took me a lot of time to find "interesting" requests coming from a single app. I've significantly upgraded my approach (though it could definitely be more efficient), and in this post I wanted to share it with you.TL;DRI have created a small guide and a Python notebook that allow anyone to record mobile app traffic and find surprising things in it. Here's the link to a GitHub repo with it. The initial setup takes 10-30 minutes. Analysis using this algorithm took me about 10 minutes per app - you can definitely dig deeper and get lost for hours if you find something interesting in there.. Follow the readme or the guide below if you'd like to try!I came up with an idea: it would take me hundreds of hours to go through each app and record the traffic, though I would love to do that – let's not blindly trust some table from the internet, but find out for ourselves. I copied the Gravy Analytics Google Sheet and created a simple form that you can fill in (no personal info is collected) that writes to that Google SheetLink to the tableLook up any app you already ...