What you open never leaves your device. Every one of these tools is compiled to WebAssembly and runs inside this browser tab. There is no server to send anything to, and none of them makes a network request while it works. You can open your browser's network panel and use any of them: nothing goes out.
A recording is the most personal thing in this workspace. It carries a voice, a room, and whatever happened to be said while it was running. None of it goes anywhere.
No tool on this site asks for a microphone, and the browser will never prompt you for one — there is no code that could use it. The tuner tunes a file rather than an instrument, the tempo tool reads times you type rather than taps it hears, and the metronome writes a click track instead of ticking. Each of them says so on its own result, because a tool that looks like it should listen and does not is worth explaining once rather than filing a bug about.
Every result is a file to open in whatever you already listen with. A player would be a second application, and the honest thing is to say so rather than to draw a button that does not work.
Each tool remembers your settings, and remembers your input while it is small enough
to be worth keeping, under about eight kilobytes. It is kept in your browser's own
localStorage, on your machine, and is never transmitted. A recording is
far larger than that and is never stored — closing the tab forgets it. Your chosen
language and theme are stored the same way.
No account, no sign-up, no cookies of our own, no analytics script, no fingerprinting, no error reporting. The pages carry no third-party JavaScript except the advertising described below.
These pages carry advertising, which is what pays for hosting them. An advertising network sets its own cookies and sees your IP address and the page you are on, in the same way it does on any other site. It does not see what you open in a tool: that data is never part of the page's markup and is never sent anywhere. If you would rather it saw nothing at all, an ad blocker breaks none of the tools.
Opening a file reads it into the tab's memory and no further. Saving a result writes it with your browser's own download mechanism. Neither passes through a server.
MP3, FLAC, Ogg, AAC and AIFF are recognised here and their headers are read and described, but their audio is not decoded: a decoder for any one of them is a larger program than this whole application. A tool that needs samples says which format it was given and refuses by name rather than producing something plausible. WAV is carried whole, in and out.
This workspace ships no binary assets of any kind, and that includes the examples. The example button synthesises what it needs — a sine tone, a short burst of shaped noise standing in for speech — and the interface says so. It turns out to be the better fixture as well: a computed sound is identical every time, so comparing two settings compares the settings rather than the recording.
The loudness meter is not a broadcast measurement: LUFS weights the spectrum by hearing and gates the quiet parts, and this does neither. The sweep is not a hearing test, because played through speakers it measures the room and the speakers as much as your ears. The exposure table is the arithmetic of a published limit, not a measurement of anywhere you are. Each of those sentences is on the result rather than only on this page.
The size limit is thirty-two megabytes, checked from the file's own header before the samples are read, and the refusal carries the size it found. A frequency past half the sample rate is refused with both numbers, because a tone above it folds down and comes out lower than asked for — which would be a wrong answer given confidently.
The same tools are also built as a desktop application. It has no network code at all — not for updates, not for anything — and stores its settings in one small file in your user configuration directory.
If this ever changes, this page changes with it, and the change will be visible in the project's history rather than announced quietly.