Privacy

What stays in your own browser

The case you are working on, the groups and floor plans you keep, and the notes a player makes all live in your own browser’s storage. They go nowhere. Clear your browsing data and they are gone, for us too, because we never had them.

We set one cookie: which language you chose. If you are in a club or join a live round, there is a second one per club or round, see below. A browser that keeps anything of ours in its storage also gets a cookie that says only that (has-progress=1), so that storage can come along if the site moves to a new address. That is all. Visits are counted, and how fast the pages load is measured, by our hosting provider, with no cookie and nothing that follows you from site to site. There are no third-party trackers.

What a share link contains

A share link is short, for example murdx.com/z/k7m2p9x. Behind those seven letters we keep the case on our server: the names, the faces, the rooms and where the body lies. Anyone with the link can open the case, including the names you typed.

If you share a case you made while signed in, the link ends in ?r= and eight letters. Those letters tell nobody who you are; only we can match them to your account, so you get a point in the week standings when somebody else solves that case. We then keep that this player solved your case through your link, and it goes as soon as either of you deletes the account.

There is also a long version of the same link, with the whole case in the address itself; it works without us keeping anything. Because the case is then in the address, it lands in the logs of the server that serves the page. So do not put anything in a case that could not go in an email. A class list of first names is fine; sensitive details are not.

Want us to remove a short link? Send it through the feedback form (the Beta button) and we will take it down.

Share links are not in Google: we explicitly ask search engines not to index them.

The only thing that leaves your browser

If you use “Draw it” to have a floor plan drawn from your description, we send two things to Google’s language model service: the names of the rooms, and the sentence you wrote. Nothing else: no suspects, no victim, no case.

If you do not use that button, nothing leaves your browser beyond fetching the page itself.

If you create an account

Then we do keep something: your email address, a name, and the cases you deliberately put in your library. A kept case contains the names you typed, usually children’s, and sits on our server until you remove it.

When you make an account you tick that you agree to the terms, and that you are 16 or older or are making the account together with a parent or carer. We keep which version of the terms that was and when, because an account is an agreement between us and that is the record of it.

Purchases go through Stripe. We never see card details; Stripe tells us only that a payment was made and how much.

You delete your account yourself, on your account page, and it is immediate and final: account, sessions, kept cases, puzzle books, saved groups and credits go. Only the purchase record stays, without your name, because the books require it.

Your age and the leaderboard

On your first visit we ask how old you are, with three choices: under 13, 13 to 15, or 16 or older. We keep only that choice, no age and no date of birth. It is kept in your own browser or on your phone, and on your account if you have one. You can change it on your account page.

We use it for the leaderboard: anybody under 13 appears there without a face and without a flag, with a neutral name such as Sleuth 4821.

The leaderboards for the case of the day and the week show the name you choose for the leaderboard, your face if you have made one, and a small flag if you choose a country yourself. There is no flag unless you choose one. If your name looks like your email address, we show a neutral name instead until you choose one. Your email address is never on a leaderboard.

If you are in a club

A club asks for no account and no email. We keep the club name, the nickname you choose, the face you make in the face maker (a short code, never a photo), the cases in the club and the times our server measured.

Who you are in a club is remembered by your own browser, with a random key in a cookie only our server can read. We keep only a fingerprint of that key, so our database cannot be used to sign in as someone else.

You can leave a club yourself; the founder can remove someone or close the whole club, which deletes everything in it at once. A club nobody uses for 90 days disappears by itself, with everything in it.

If you join a live round

A live round asks for no account. We keep the name you type, how many people you have put on the plan (for the bars on the big screen) and your time if you solve the case. The case itself is kept with the round, with the names whoever runs it put in.

Who you are in the round is remembered by your browser with a cookie for that round, just like a club. Whoever runs the round can take a name off the board.

After 30 days we take the names and the case off the round. All that is left is how many people solved it.

Feedback, and what we measure

If you send feedback, we keep your message, the page you were on (without what the link of a case contains), the language and the kind of device, for example “Android, Chrome, 390x844”. Your email address only if you fill it in yourself, so we can answer. None of it is tied to an account.

We also count, per day, how often something happens: a case made, shared, printed, played or solved. Only the number, without who, without the case and without an address.

When you finish a case in the studio, we keep how it was made: how many people and rooms, how big the board is, which level you chose and which it became, and how long you worked on it. Our server reads those numbers out of the case and throws the case itself away: no names, no rooms, no link, nothing about who.

How far you are through the ready-made cases is kept by your own browser. The first time you reach a step (your first case, 10%, 25%, half, all of them, or a whole level), your browser adds one to that day’s counts, once, with nothing that recognises you or your browser.

The same way we count how many different devices open the site and start a case: your browser remembers the day, week and month it last reported itself, and only reports again once those have passed. Only a word goes to that day’s counts, nothing that identifies you or your device.

When you solve a case or show its answer, we keep how it went, to see whether the levels are right: the level, how hard our own measurement finds the case, your time, and how many hints and wrong checks. For a ready-made case its number, for the case of the day the date. Without who, without names, without the link and without an address.

The app

In the Android app, without an account everything stays on your phone: your streak, your times, your notes and the cases you make. With an account we keep your name, email address and solved cases, just as on the website. If you share a case, use a club or send feedback, only that goes to our server.

The app uses no ads, no advertising ID, no location and no photos. The daily reminder is scheduled on your phone itself; nothing goes to a push service.

You erase your data in the app under Me. How to delete your account, and what happens to your data then, is at murdx.com/delete-account.

How long we keep it

An account, and what is in it, until you delete it yourself.

How a case went and how a case was made: 13 months, then it is deleted automatically. The daily counts hold nothing about anyone and are kept.

A puzzle book made without an account is deleted 12 months after its link was last opened. A puzzle book in your account stays until you delete it or delete your account. A puzzle book’s pages are not in search engines: we explicitly ask them not to index them.

Feedback: we remove your email address after 12 months and the message itself after 24 months. Clubs and live rounds are described above.

Why we may do this, and what you can ask

MurdX is made by 771Labs. 771Labs is responsible for the data on this site; you reach us at info@murdx.com or through the feedback form.

We keep an account because you create it: it is the agreement between us (GDPR article 6(1)(b)). We count and measure to make the game better without knowing who you are; that is our legitimate interest (article 6(1)(f)). Your email address is on feedback only if you fill it in yourself.

You can always ask us what we hold about you, have it corrected or deleted, or object, through the feedback form. You delete your account yourself on your account page. If you disagree with how we handle your data, you can complain to the Dutch Data Protection Authority (Autoriteit Persoonsgegevens).

Who helps us: Vercel hosts the site, the database is at Neon in Frankfurt, Stripe handles payments, Sentry is told when something goes wrong on the site, and Google draws a floor plan when you ask for one. They process only what is described above, on our behalf.

Children

This is built for classrooms, so it probably has children’s names in it. That is exactly why we ask nothing about who you are and keep as little as we can. A name in a case means nothing to us: we do not know who it is and do not look.