How to stop websites tracking you: cookies, scripts and fingerprinting

Every website you visit can try to recognise you, and advertising companies link those visits together into a profile of you across the internet. The ways they do it have changed a lot since 2014: Flash cookies are gone, and the biggest threat now is fingerprinting.

How you are tracked

• Cookies: small files a website saves in your browser. Third-party cookies come from advertisers embedded in many sites, so they see you everywhere.
• Scripts (JavaScript): code that runs in the page. Most sites need it, but tracking scripts use it to record what you click, how you scroll and what you type.
• Fingerprinting: websites measure your browser: screen size, fonts, graphics card, time zone, language, extensions and more. Together these are often unique, so you can be recognised even with cookies deleted.
• Your IP address: your internet connection's address shows your rough location and your provider.
• Logins: if you are signed in to Google, Facebook or similar, they know it is you, on their own sites and on many others.

Simple steps that stop most tracking

1. Use a privacy browser. Good choices: Mullvad Browser or Tor Browser on computers (both are built to make everyone look the same), Brave, or Firefox with strict tracking protection. On GrapheneOS, Vanadium is a strong default.
2. Block third-party cookies. It is on by default in Brave, Safari and Firefox's Strict mode.
3. Add an ad and tracker blocker like uBlock Origin (Firefox). Do not install lots of extensions: each one makes your browser easier to fingerprint.
4. Do not stay signed in to big accounts while you browse other sites. Use a separate browser or profile for them.
5. Clear cookies when you close the browser, or use private windows for one-off visits.
6. Hide your IP address with a trusted VPN or Tor.

For stronger anonymity

• Tor Browser (or Tails) hides your IP address and makes your browser look like every other Tor user. Do not resize the window to full screen, do not add extensions, and do not change settings, because all of these make you stand out.
• Tor Browser's Security Level (shield icon) set to Safer or Safest turns off risky features like JavaScript on many sites. Use it when anonymity matters more than convenience.

Check your browser

The EFF's free Cover Your Tracks test (coveryourtracks.eff.org) shows how well your browser resists tracking and fingerprinting.