What Prelude keeps, and why

Prelude is in alpha, run by one person (Brian Cook). This page says, in plain words, what happens to the music you upload. Last updated 8 November 2026.

What is stored

Your email address, so you can sign in. Sign-in is handled by Amazon Cognito, which keeps your password; Prelude does not store it. When you use Change password in your library, Prelude passes your current and new password straight to Cognito to make the change and keeps neither.
The PDF you upload, and the title you give it.
Photos of the pages, if you add a piece with your phone. Your phone shrinks each photo before sending it. When you choose "Read the music", the photos become the piece's PDF and the separate photos are deleted.
Page images made from that PDF.
What Prelude read from each page (the notes, rests, clefs and other marks it found).
Your corrections: what you fixed, added or removed on the correction page.
Pages you add to a piece later (an insert, from Insert… or Add pages / insert): the PDF or photo, kept with that piece like the rest of it.
Your Reflow layout: the choices you make in Reflow for a piece (note size, letters, page breaks, bars you copied, moved or removed, and changes you make in Edit music), so the piece looks the same on your other devices.
Feedback and problem reports, when you send one with the Feedback tab or Something’s wrong here… in Reflow: your message, your email address, which piece, page and bar it is about, the type of browser and the window size, any recent error messages from the page, and a screenshot of the page if you leave that box ticked. Each report is emailed to Brian so he can fix the problem.
Whether a piece is public domain: your answer when you add a piece (public domain, under copyright, or not sure), when you gave it, and whether you offered a public-domain piece to Prelude’s free public-domain library. You can change the answer in your library at any time. The library does not exist yet, so nothing is shown to anyone. When it opens, only public-domain pieces you offered can be in it: the corrected music, never your name or account. Prelude may compare the corrected music of several people’s copies of the same public-domain edition to check it is right.
A testing log, only if it is switched on for your account: it is off for everyone unless Brian switches it on for an account (today only his own, for testing). While it is on, Prelude records what you click and press in the editor, what the page showed a moment later (for example how many pages or letters it drew) and any error messages, with the piece and your browser type. It is kept for 14 days, then deleted.
Your account settings: your page margins, your highlighter colours for sharps and flats, and your defaults for new pieces (note size, letters in the notes, fingering level, bars per line), so they are the same on every piece and every device. Nothing else about you is kept with them.
A few settings in your browser only (not on our servers): your paper colour and which help tips you have already seen.
Short technical logs (for example "page 2 took 50 seconds"), used to find and fix problems. They are deleted after 30 days.

Everything is kept on Amazon Web Services in the United States. Nothing is sold, and there is no advertising or tracking.

Why

To show you your pieces. Prelude needs your scan and what it read to build the page where you correct it.
To make Prelude read music better. Your corrections show exactly where the reader went wrong. They are used to improve it, for you and for everyone else.

Who can see it

You. Your library and your corrections need you to be signed in, and only show your own pieces.
Brian, who runs Prelude. He can see uploaded pieces and corrections, and looks at them to fix problems and improve the reader.
Nobody else. Your scans are never shown to other users.

One thing to know: the correction page for each piece sits at a long, random web address that only you are given. Anyone who had that exact address could open the page and see the page images. Your corrections and your account would stay private, because they need you to be signed in. Don't share that address if the music is private.

Adding pages with your phone: the QR code (or the 6-character code) lets a phone send photos to one piece for 30 minutes, without signing in. Whoever has that code during those 30 minutes can add or remove photos of that one piece and see the photos sent so far. It cannot open your library, your other pieces or your corrections. The code stops working when the 30 minutes are up, when you make a new code, and when you choose "Read the music".

How to delete it

One piece: in your library, choose Delete next to the piece. That removes the PDF (or the phone photos), any pages you added, the page images, what Prelude read, your Reflow layout and all of your corrections straight away. The database keeps a safety backup for up to 35 days, after which it is gone too.
Your whole account: sign in, open the Feedback tab on the right edge of any page, choose Question and write “Please delete my account”. It goes straight to Brian. Your account and everything in it will be deleted.

Your part

Only upload music you have the right to use, such as parts you own or were given to play.

Questions about any of this: send them with the Feedback tab on any page (choose Question); they go straight to Brian.