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Cookie policy

We only use the cookies and local storage the site needs to work and to remember your choices. No analytics or advertising cookies and no third-party cookies — our usage statistics work without cookies — which is why we don't ask for your consent.

Last updated: 17 October 2026 · This English version is provided for convenience; if it differs from the Spanish version, the Spanish version prevails.

01What they are

Cookies are small files that a website stores in your browser to remember information from one visit to the next. Local storage (localStorage and sessionStorage) is a similar technique that keeps data in your browser without sending it to the server.

02Cookies we use

They are all first-party — set by acotario.eu — and strictly necessary:

CookiePurposeDurationType
auth.session_tokenKeeps you securely signed in. Only exists if you sign in to your account.30 days, renewed with useTechnical · authentication
auth.session_dataSigned copy of your session that avoids querying the database on every page.5 minutesTechnical · authentication
auth.stateProtects sign-in with Google against request-forgery attacks. Only during that process.5 minutesTechnical · security
NEXT_LOCALERemembers the language you chose. Only created if you choose a language other than your browser’s.1 yearTechnical · preference
nf-unitsRemembers the units you chose (cm, mm, m or feet and inches). Only created if you change units.1 yearTechnical · preference

Over secure connections (HTTPS), session cookies carry the “__Secure-” prefix, for example __Secure-auth.session_token.

03Local storage

We also keep the following data in your browser; it is never sent to our servers:

KeyPurposeDuration
nf-themeYour theme: light, dark or the system’s.Until you delete it
nf-unitsYour units, alongside the cookie of the same name.Until you delete it
nf-profileThe user profile you set without an account (stature, wheelchair…) to adjust the sheets.Until you delete it
nf-news-seenWhen you last opened Updates, so the header can mark the ones you haven't seen yet.Until you delete it
nf-pending-save · nf-pending-exportThe sheet you were saving or exporting while you create an account or sign in, so you don’t lose it.Until you close the tab

All of the cookies and data above are strictly necessary to provide the service you ask for: signing in, keeping your session secure or remembering the language, units or theme you choose. That is why they are exempt from consent under article 22(2) of the LSSI-CE and the Spanish Data Protection Agency’s Guide on the use of cookies. We still tell you about them here.

We don't use analytics, advertising or social media cookies, and we don't allow third parties to set cookies through the website. The usage statistics described in the privacy policy use no cookies or browser storage.

If we ever add analytics or other cookies that require consent, we will update this policy and ask for your consent before setting them.

05How to manage them

You can view and delete cookies and local storage in your browser settings: Chrome, Firefox, Safari or Edge.

If you block them, the library will keep working, but you will not be able to sign in and we will not remember your preferences.

06Changes and contact

If the cookies we use change, we will update this policy and its date. For any question, write to [EMAIL].