Null

Privacy Policy

Effective date: August 9, 2026

The short version. Null works offline — loading, playback, and comparison all happen on your device, and nothing is uploaded automatically. The one exception is Sharing: if you choose to share a session, the selected audio, its details, and any notes are uploaded so someone can open the link, then automatically deleted after 3 days. The app also sends a small set of anonymous usage events (like "a session was created") to help us find bugs — see App usage events below. The only personal data Null stores is an email address, and only if you choose to enter one. This site uses cookieless, aggregate analytics to see how many people visit — see Website analytics below. There are no ads or tracking SDKs.

About this app

Null (“the app”) is an offline A/B mix-comparison tool for iOS. You load versions of a track and switch between them by ear. All track loading, playback, waveform analysis, and comparison happen entirely on your device, and Null never uploads your audio in the background or automatically. The only time audio leaves your device is when you explicitly share a session — see Sharing a session below.

What we collect

An optional email address. During onboarding (or if you tap a “notify me” prompt), you may enter your email address to hear about the app’s launch and occasional product news. Providing it is entirely optional, and skipping it does not limit any feature of the app.

Aside from the content you actively upload when you share a session (see Sharing a session) and the anonymous usage events described below, the app does not collect your name, location, or contacts. This does not apply to the usenull.app website itself — see Website analytics below.

App usage events

Null sends a small number of anonymous events to our own backend — for example, that a session was created, a share was opened, or the app hit an error. This helps us find bugs and see which features get used, without watching individual people.

These events come from a fixed, short list — things like "session created" or "version switched" — never free text, filenames, session names, or any other content from your library. There is no device ID, advertising ID, account, or other identifier attached to these events, so they cannot be linked back to you or to a specific device over time. They cannot be used to track you across other apps or websites, and Apple's App Tracking Transparency prompt does not apply because we don't do that kind of tracking.

How we use your email

Solely to send you occasional updates about Null — for example, launch news and significant new features. We do not sell, rent, or share your email address, and we do not use it for third-party advertising or cross-app tracking.

How your email is stored

Submitted email addresses are stored with Resend, the email service we use to manage our update list and send messages. Resend processes this data on our behalf; see their privacy policy for how they handle it.

If you enter an email while offline, it is held only on your device until the app can next reach our signup endpoint, then sent and removed from local storage.

Website analytics

The usenull.app website uses Cloudflare Web Analytics to see how many people visit and how the site performs. This tool does not use cookies or browser storage, does not fingerprint your device, and cannot follow you across other websites. It only reports aggregate counts, such as total page views, and never builds a profile tied to you individually. This analytics tool applies only to the website — the Null app itself remains fully offline and collects no usage data.

Null lets you share a session so someone else can hear your versions. This is entirely optional and happens only when you tap Share.

When you share a session:

The audio you’re comparing — your master files, plus a compressed preview generated on your device for in-browser playback — is uploaded, together with the session’s details (title, artist, tempo, key, version labels, loudness) and any review notes you’ve added.
Those files are hosted on Cloudflare R2 and a small backend service (Railway), solely to make the share link work — streaming the preview, downloading the master, and opening the session in the app.
The link is unguessable and can be opened by anyone who has it. There are no accounts, and we don’t ask — or know — who you share it with.
Shared files automatically expire and are permanently deleted after 3 days. Once a share expires, the link stops working.
Your device is tagged with a random, anonymous identifier — not your name, email, or Apple ID — so the app can recognize shares it created. It does not identify you.

If you never use Share, none of this applies: no audio, notes, or session details ever leave your device.

Your choices

You can use the entire app without ever providing an email.
Sharing is optional, and every shared link automatically expires and is deleted after 3 days.
Every update email includes an unsubscribe link; unsubscribing stops all future messages.
To have your email removed entirely, contact us at the address below and we will delete it.

Children

Null is not directed to children under 13, and we do not knowingly collect personal information from children.

Changes

We may update this policy as the app evolves. Material changes will be reflected here with a new effective date.

Contact

Questions or requests: privacy@usenull.app