Privacy Policy

Effective date: 26 July 2026

The Stack (in Spanish, La Pila) is a free personal tracker for movies, TV shows, books, and video games. It is built and run by Almudena Bernardos, an independent developer based in Spain, who is the data controller for the app. For anything privacy related, write to privacy@onthestack.app.

This policy covers the web app at its.onthestack.app and the site at onthestack.app. When the iOS and Android apps arrive, it will cover those too.

The short version

You can use The Stack fully without telling us who you are. No name, no email, no password. If you choose to add an email, it is used for exactly one thing: letting you recover your library on another device. There are no ads and no advertising trackers, your data is never sold or shared for advertising, and the anonymous usage statistics we keep can never be tied to who you are.

What we collect, and why

An anonymous account. The first time you use the app, it quietly creates an account for you with a random identifier. That identifier is not your name, your email, or anything about you.

Your library. The titles you save, their media type, their status (pending, finished, and so on), the dates you added, started, or finished them, your genre tags, and references to cover images. This is the whole point of the app, and it stays yours.

Your language preference. Stored with your account so the app, and any emails we send you, arrive in the right language.

Your email, only if you add one. Adding an email is optional and exists solely so your library is recoverable across devices.

Signing in, without passwords

If you add an email, you sign in with a one-time code sent from hello@onthestack.app. Emails are delivered through Resend, hosted in Ireland (EU). There are no passwords to store or leak, and we do not track whether you open or click our emails.

Searching the catalogs

When you search for a title to add, your typed query goes to the catalog that can answer it:

• TMDB (movies and TV) is queried directly from your device, so TMDB's servers see standard request data such as your IP address.
• IGDB (games) is queried through our own server, so IGDB does not see your device directly.
• Open Library (books) is queried directly.
• AniList (manga) is queried directly from your device, so AniList's servers see standard request data such as your IP address.
• Metron (comics) is queried through our own server, so Metron does not see your device directly.

Cover images load from these services' image servers. Each service receives only what is needed to answer the request. None of them receives your account data.

Cached title information (posters, descriptions) is refreshed from its source roughly every five months, which is a licensing requirement of TMDB. Your own data (statuses, dates, tags) never leaves your account.

Where your data lives

Your data is stored in Supabase, a managed Postgres database with row-level security, meaning each user can only access their own data. Region: West EU (Ireland). The app itself is hosted on Vercel.

In your browser, the app uses localStorage strictly for your session and preferences. No advertising cookies, no third-party trackers, no cross-app tracking.

Who else is involved

We use a small number of service providers (processors) that handle data on our behalf: Supabase (database), Resend (transactional email, EU), Vercel (hosting), Amplitude (usage statistics, EU), and RevenueCat with Stripe (tips and payments). The catalog sources, TMDB, IGDB, Open Library, AniList, and Metron, are independent services that receive your search queries as described above.

We do not sell personal data, and we do not share it for advertising. Ever.

Usage statistics

To understand which features are actually used, the app sends a small set of named events to Amplitude, an analytics service hosted for us in the EU (Frankfurt). An event looks like "item added, type: movie". Events carry the same random identifier as your account plus basic technical context (device type, operating system, screen size), and nothing about you: no name, no email, no titles from your library, and no IP address. Amplitude is configured to set no cookies and to store no identifiers of its own on your device; nothing is placed there beyond what the app already needs to work, which is why there is no consent banner. If you delete your account, the identifier is destroyed with it, and the statistics that remain can no longer be connected to you.

Tips

If you choose to leave a tip, the payment is handled by RevenueCat and processed by Stripe (or by Apple or Google on the mobile apps, when those arrive). Your card details go to the payment processor, never to us; our database never sees them. What we receive is a record that a tip was made, tied to your account identifier, so the app can thank you and refunds can be handled by the platform you paid through.

Legal bases (GDPR)

• Performing the service you asked for: storing your library, your preferences, your email if you add one, and processing a tip if you leave one.
• Legitimate interests: keeping the service secure and preventing abuse, and the usage statistics described above, which are cookieless, pseudonymous, and never based on the contents of your library.

How long we keep your data

For as long as your account exists, with one housekeeping rule on top: any account inactive for 2 years is removed. If yours has an email, we will write to you there before that happens. When your account is deleted, its data is deleted with it. Usage statistics are kept in pseudonymous form: deleting your account destroys the only link, and what remains can no longer be associated with you.

Deleting your account

Today, email privacy@onthestack.app and we will delete your account and all its data within 30 days. An in-app "Delete account" option is planned. Note that signing out does not delete anything; your library waits for you.

Your rights

Under the GDPR you can ask to access, correct, delete, or receive a copy of your data (portability), and you can ask us to restrict or object to certain processing. Write to privacy@onthestack.app and we will help. You also have the right to complain to a supervisory authority; in Spain that is the AEPD (www.aepd.es), or the authority in your own country.

International transfers

We keep data in the EU where possible (database, email, and usage statistics are EU-hosted). Some catalog providers, such as TMDB and AniList, are US-based and receive search requests, including standard technical data like your IP address, when you search their catalog. No account data is sent to them. If you leave a tip, RevenueCat, a US company, receives the purchase record, and Stripe processes the payment; both receive only what payment handling requires, never your library.

California residents (CCPA)

You have the right to know what personal information we hold and to request its deletion; use privacy@onthestack.app for both. We do not sell or share personal information as defined by the CCPA, and we will never treat you differently for exercising your rights.

Children

The Stack is not directed at children under 14, the digital consent age in Spain, and we do not knowingly collect their data. If you believe a child has provided us data, contact us and we will delete it.

Changes to this policy

If this policy changes in any meaningful way, we will update this page and note it in the app. The effective date at the top always tells you the current version.

Contact

Almudena Bernardos, data controller, Spain. privacy@onthestack.app