Notch
Native iOS Swift · SwiftUI For sale — $7,500
A finished iOS app, never released

Every tinnitus app plays you rain.
This one plays your sound.

Six sliders until the phone is playing the exact thing in your head. From that one piece of information, everything else in the app follows.

6,200Hz
Night coverage — notch mode
1005002k8k16k

Drag the ribbon. The masking noise carries a one-octave hole carved exactly where the tinnitus sits, so the sound goes around it instead of sitting on top of it. Two cascaded notch biquads, zero frequency drift — the hole never moves. This is the technique the app is named after.

5,694
lines of Swift, 34 files
71
tests, all passing
0
third-party dependencies
25
commits of history
$9.99
StoreKit 2, already wired
What the app does

Four steps, in the order a user meets them.

The order matters: nothing after the first step works until the sound has been rebuilt, because every later feature is derived from it.

01 — Sculpt it

Rebuild the sound from scratch

Four starting families — whistle, hiss, crickets, hum — then six parameters: pitch, width, fine tune, tremble, warmth, drift. A live spectrum and a live frequency readout follow every move. Volume is capped at 0.6 of full scale and labelled only until you hear it; louder does not help, because the audience is people whose ears are already having a hard time.

Left and right ears carry their own six parameters and their own decorrelated noise voice.

"That's him."

The Sculptor screen: a live spectrum peaking at 6.20 kHz above pitch and width sliders.
02 — Show it

The sound becomes an object you can hand to someone

The sculpt exports as a card — a PNG, a PDF, and an eight-second WAV rendered by the same synthesis engine, faded in and out so it never clicks. Not an approximation of the sound: the sound.

This is how a person finally demonstrates to a partner, a parent or a doctor what they have been trying to describe for years. It is also the feature that travels — the one people screenshot.

The identity card: a named sound at 6,200 Hz with its spectrum fingerprint and a share action.
03 — Cover it

Masking shaped around the frequency, not over it

Two modes. Blanket lays a wider band on the same centre. Notch carves a one-octave hole exactly where the tinnitus sits, so the noise wraps around it.

Twenty-second fade-in, a taper to 70% across the session, a ninety-second fade-out tail. Background audio, lock-screen controls, and a route-change policy that pauses instead of jumping to the speaker when the AirPods come out at 3am.

Night coverage screen with blanket and notch modes and a duration selector.
04 — Try to stop it

The feature people tell other people about

Residual inhibition: after about a minute of a stimulus matched to the frequency, tinnitus often goes quiet for a while — seconds to minutes. The app calibrates the level with the user step by step, plays it, then switches the audio engine off entirely — real silence, not a quiet hiss — and starts a stopwatch.

Framed as an experiment, never as a promise. When nothing happens, the copy refuses to make the user feel it was their fault.

The Silence screen mid-session, counting down with the calibrated stimulus playing.
Why the audio is the moat

Most competitors ship looping MP3s. This generates every sample.

The whole engine is one pure function — parameters to DSP coefficients to samples — deterministic, seeded, and pinned by tests. That is what makes the notch land exactly on the user's frequency, and what makes the exported audio real.

One render block

A single AVAudioSourceNode, with a lock-free triple buffer between the control thread and the audio thread.

It cannot click

A hard cap on master gain and a one-pole ramp on every gain change. Nothing steps.

Pinned by golden values

Render snapshots and golden tests mean a buyer can refactor the DSP and know instantly whether the sound changed.

A real design system

Tokens for colour, type, spacing and motion, plus reusable components. The whole app re-themes from one file.

Nothing leaves the phone

No network code exists in the app. No accounts, no analytics, no backend. The App Store privacy label is empty.

No medical claims

Deliberate, everywhere. A test fails the build if a banned word reaches the store description.

Status, honestly

Never released. No users, no downloads, no revenue.

What is for sale is a finished, tested, documented product that is ready to submit — not a business with a track record. Buyers price those two things very differently, and the fastest way to waste everyone's time is to be vague about which one this is.

Every feature is built: the icon, onboarding, accessibility, the paywall, the tests, the documentation. What the next owner still owes before shipping is written down in docs/SETUP.md, and it is verification rather than development:

  • A device run of the Silence protocol
  • A pass on a physical iOS 18 device
  • One live purchase round-trip through App Store Connect
  • An overnight audio session

That list stays in the package. A buyer who reads it trusts everything else more — and the alternative is that they find it after paying.

The transfer

What changes hands.

Included

  • Full source and the complete git history, delivered as a git bundle or a transferred private repository
  • The name Notch and the app icon, in all three iOS 18 variants
  • Documentation: architecture, a full feature inventory, the evidence behind the sound design, the setup and rebranding checklist, the copy voice, the roadmap
  • A 30-minute call walking through the architecture

Not included

  • The seller's Apple Developer account or developer identity
  • Any App Store Connect record
  • The Italian-language working copy, which stays with the seller

Day one for the buyer

  • Signing team, bundle identifiers, the IAP product id, and the app name if renaming — one table in the setup doc
Every screen

Eight screens, captured from the simulator.

Family picker with four starting points.
Family picker
The Sculptor.
Sculptor
Identity card.
Identity card
Library of saved sounds.
Library
The Silence session.
Silence
Night coverage.
Night coverage
Diary check-in.
Diary
The paywall.
Paywall
$7,500Asking — open to offers

Listed on Indiemaker, where offers are free to make and funds are held in escrow until the buyer confirms the transfer. Ask for the architecture doc before you make one — it is the fastest way to tell whether this is worth your time.