Privacy policy
Last updated October 30, 2026
ASU Class Watcher is built to need as little about you as possible. There are no accounts, and we never ask for your name, email, phone number, or ASU login. This page lists everything we do keep.
The short version
- We store the class numbers you watch, any study-room alert times, your alert settings, and a random topic that delivers your alerts. Nothing in that identifies you.
- No cookies, no ads, no tracking scripts, and no selling or sharing of data.
- We count visits as anonymous daily totals that can't be traced back to you.
- Tap Stop watching and that class is gone from our list.
What we store
| Data | Why | How long |
|---|---|---|
| Class numbers you watch | To check them and alert you | Until you tap Stop watching |
| Your alert settings | Minimum seats, and whether reserved seats count | Removed with the class |
| Your private topic | A random code like seat-903528… that links your phone to your watches | Until you remove your last class |
| Study-room alerts | The library, day, time window and group size you asked about | Until the window starts or you remove it |
| "Already alerted" markers | So you get one alert per opening, not repeats | Cleared when the class fills again or you remove it |
| Feature requests | Only the text you type, with nothing attached to it | The newest 200 are kept |
| Daily visit totals | Page views and an estimated count of different visitors | 90 days |
| Rate-limit counters | To stop scripts from flooding the site | One hour or less |
How visits are counted
When the page loads, it sends a small request to our server. The server turns your network address, browser type, and the date into a one-way hash mixed with a secret, then adds it to a counter that can only estimate how many different visitors there were. The original values are not stored. Because the date is part of the hash, a visitor on Monday can't be matched to the same visitor on Tuesday. Known bots and link previews aren't counted.
How rate limiting works
To stop abuse, we count requests per network for a short window. These counters are keyed by a keyed hash of your network address, not the address itself, and expire on their own within an hour.
What stays on your device
Your topic is saved in your browser's local storage under seat-topic, so you can come back and manage your list. It only leaves your browser when the page talks to our server about your list: loading it, adding a class, or removing one. Clearing your browser's site data removes it; your watches keep running until you remove them.
What we don't collect
- Names, emails, phone numbers, or ASU logins.
- Cookies of any kind.
- Ads, advertising IDs, or third-party analytics or tracking scripts.
- Your location or contacts.
Services we rely on
A few outside services make the site work. We don't sell or share your data with anyone else.
- Vercel hosts the site and runs our server code. Like any web host, it handles your network address to deliver pages and may keep standard request logs under its own privacy policy.
- Upstash runs the database that holds the data listed above.
- ntfy delivers your alerts. It receives the alert text (the class name and seat count) for your topic. Anyone who knows your topic can read those alerts, so keep it to yourself. See ntfy's privacy policy.
- Google Fonts supplies the page font on devices that don't have Apple's system font. Your browser fetches it from Google, which receives your network address as part of that request. See Google's privacy policy.
- ASU's public class search is where seat counts come from. Our server asks it about class numbers only; nothing about you is sent.
- ASU Library's public room-booking pages (LibCal) are where study-room availability comes from. Our server asks about libraries and days only; nothing about you is sent. You book rooms on the library's site, under its own policies.
Your choices
- Stop alerts for a class: tap Stop watching next to it. It's removed from our list right away.
- Remove everything: stop watching every class. Your settings and alert markers go with them, and your topic is no longer used.
- Stop notifications on your phone: unsubscribe from the topic in the ntfy app.
Security
Everything between your browser and our server is encrypted with HTTPS. The site blocks outside scripts and being embedded in other sites, and the parts that run the checks are protected by a secret key.
Changes
If what we store changes, we'll update this page and the date at the top.
Questions
ASU Class Watcher is an independent student project. To ask about your data or request a change, use the Request a feature box on the home page. Don't include personal details there.