Cookies and local storage

Version 1 · 15 September 2026 · revised on 19 September 2026

This is a courtesy translation. The Spanish text is the one that binds; if the two differ, the Spanish version prevails. Read it in Spanish.

Yalerta uses no tracking cookies and no third-party analytics. The little it stores on your device is there to make the service work, and all of it is listed here.

In two lines

No advertising, no third-party tracking, no fingerprinting. We store your session and your preferences; we measure use of the website without cookies and use of the app with a random identifier that is not linked to your account. That is why you see no banner when you arrive.

What the website stores

Name	What for	How long
`sb-…-auth-token` (local storage)	Your session. It is created the first time you do something that needs one (signing up, reporting content, voting, saving zones), not when you look at the map.	Until you sign out or delete your account.
`plaze.device` (local storage)	A random identifier for this browser, so that alerts do not arrive twice. Only created if you turn on notifications.	Until you clear the site’s data.
`/sw.js` (service worker)	Receiving push notifications. Only installed if you turn them on; it stores nothing for offline use.	Until you remove it from the browser.
`yalerta-lang` (cookie)	The language you chose on the website, so that the home page keeps to it rather than going by your browser’s language. Only created if you switch language.	One year.

There are no third-party cookies. The server sets no cookies.

What the app stores

On your phone, the app stores your encrypted session, a device identifier in the system keychain and your preferences: city, filters, the ‘Near you’ radius, whether you have already been through the welcome, your alerts, the active call for help and the alerts you have hidden. All of it stays on the phone and is deleted when you uninstall.

It also stores a random installation identifier (in the keychain) and a small queue of usage events waiting to be sent: which screens you open and what you do (create a zone, send an alert, open a notification), with the chosen city, the app version and the language. Never your position, the text of a note or who you are: that identifier is not linked to your account and our server cannot connect the two. The events go to our own server, not to any third party; on Android they disappear with the app, and on iOS the keychain keeps the identifier if you reinstall. What we measure and why is in the privacy policy.

Who sees your IP when a page loads

When you open a page, your browser requests the map tiles from OpenFreeMap and talks to our server (Vercel) and to our database (Supabase, in Frankfurt). Those providers see your IP address as any web server does; none of them is told who you are or uses it to profile you. Details in the privacy policy.

Why there is no banner

The law (article 22.2 of the LSSI, Spain’s information society services act) requires permission for any storage that is not strictly necessary for what you have asked for. Everything above is: the session exists because you want to do something with your account, the browser identifier because you turned on alerts, and the language cookie because you chose the language yourself.

We count visits to the website with Vercel Web Analytics, which sets no cookie and stores nothing in your browser: the server counts the visit from a digest (hash) of your IP address and browser that changes every day and is not kept, and only aggregate figures remain (page views, country, device type). With nothing stored on your device, article 22.2 does not require consent. In the app, usage events go to our server, with no third parties, and a version without that measurement would change nothing of what you see.

How to delete it

In the browser: settings → privacy → site data → search for yalerta.com and delete it. In the app: uninstall it or delete your account from ‘Me’. Signing out removes the session.