Bordun — Privacy Policy

Last updated: 15 August 2026

Bordun is a focus-sound app for iPhone. It generates its sound on your device and keeps everything it knows about you on your device. This page describes exactly what the app does and does not do with information.

The short version

Bordun has no account, no sign-in, no analytics, no advertising, and no network connection. It does not send any data anywhere.
If you turn on room listening, the app uses the microphone to measure how loud eight broad frequency bands are, about once a second. Only those eight numbers are kept in memory while a session runs. No audio is ever recorded, stored, or transmitted.
Bordun keeps a local session log (when you started, how long you listened, and the two ratings you may give at the end). It stays on your phone until you export or delete it.

Microphone

Room listening is off until you turn it on. When it is on:

The app analyses the microphone signal on the device to find intermittent sound (such as speech) and gently shapes its own texture layer to cover it.
The analysis reduces the sound to eight band-energy levels plus an “intermittency” score per band, updated roughly once per second. These values live only in memory during a session and are discarded when the session ends.
No audio samples are written to disk, kept after processing, or sent off the device. There is no code path in the app that could upload audio; the app makes no network requests at all.
iOS shows the microphone indicator while a session runs with room listening on. You can turn room listening off in Settings at any time; the app then runs with a static texture layer.

Session log

For each session Bordun stores, on your phone only:

start time, planned and actual duration, whether it finished;
whether room listening was on and, if you opted into the comparison, which arm the session ran in (“adaptive” or “frozen”);
your optional end-of-session ratings (focus 1–5, “did the sound help?”);
the home chord name.

Nothing in the log identifies you, your device, or your location. You can view the log under Settings ▸ Sessions, delete individual sessions or the whole log, and export it as JSON or CSV to wherever you choose using the iOS share sheet. Exporting is the only way any of this leaves the device, and it is entirely your action.

The adaptive-layer comparison

If you opt in, some sessions silently run with the room-tracking frozen to a neutral profile so you can find out — from your own ratings — whether the adaptive layer helps. This is explained before you opt in, you can opt out at any time in Settings, and the running results are shown to you under Settings ▸ Findings. No results are shared with anyone.

Data we do not collect

Bordun does not collect or store: names, email addresses, contacts, location, identifiers, usage analytics, crash reports beyond what Apple’s own opt-in system provides, or any audio.

Children

Bordun is not directed at children and collects no personal information from anyone.

This website

bordun.app is a static site. It sets no cookies, runs no analytics, and loads no resources from third parties. Standard server logs are kept by the hosting provider (Cloudflare) for operational purposes only.

Changes

If this policy changes, the new version will ship with the app and be posted at the same address, with the date above updated.

Contact

Questions: mark@markperryid.com · https://bordun.app