PurrPad press kit

The facts

Name	PurrPad
What it is	Menu bar app for macOS that makes the trackpad purr
Price	Free (one cat, all behaviour). $4.99 once unlocks the rest. No subscription.
Requirements	macOS 14 or later, and a MacBook with a Force Touch trackpad, so 2015 onward. Apple Silicon and Intel. External Magic Trackpads are not supported yet.
Size	About 1.2 MB
Privacy	No analytics, no accounts, no telemetry. Recordings are analysed on device and deleted.
Developer	Francesco Pavanetto, independent, Italy
Website	purrpad.app
Contact	hello@purrpad.app

Ready to paste

Descriptions

One line PurrPad makes your MacBook's trackpad purr like a cat, using real haptics at the measured pitch of an actual purr.

Short, about 50 words PurrPad is a Mac menu bar app that makes the trackpad purr. It drives the Taptic Engine at 25.75 Hz, the fundamental frequency measured from a recording of a real cat, so the purr is something you feel under your palm rather than a sound played through speakers. Sometimes the cat ignores you.

Long, about 120 words PurrPad is a Mac app that turns the trackpad into a cat. Rest your hand on it and it purrs: not an audio file, but the Taptic Engine driven as a physical actuator at 25.75 Hz, the fundamental frequency extracted from a recording of a real purring cat. Because real purrs are irregular, the app never repeats a breath; the wobble is regenerated every cycle, which is what stops it feeling like a phone on a table. The cat has moods. It usually purrs when you rest a hand, sometimes it refuses and sulks, occasionally it gets the zoomies, and it leaves you things. It goes quiet when you are on a call. Free with one cat; $4.99 unlocks the rest and lets you record your own.

The angle

The interesting part: a cat was actually measured

Most novelty apps play a sound. This one started with spectral analysis of a real purr recording, and two findings shaped everything:

The fundamental was nearly invisible

The recording's loudest peak sat at 78 Hz, but that is the third harmonic. Everything below 23 Hz had been high-passed away, so the true fundamental barely survived. Scoring candidate fundamentals by the energy at their multiples put 25.75 Hz on top: its harmonics at 52, 77, 103, 129 and 154 Hz all land on observed peaks. A haptic tap is a broadband impulse, so firing at 25.75 Hz regenerates that whole stack for free.

Real purrs do not repeat

The same recording had no repeating breath envelope at all. The strongest periodicity scored 0.33, too weak to trust; the next three were 0.12, 0.06 and 0.01. A clean looping rise and fall reads as synthetic precisely because it repeats, so the app regenerates the wobble every cycle instead.

The hardware lies a little

Tap strengths 1 to 6 actuate. The driver also accepts 15 and 16, returning success, but they produce no output at all. And the strengths are not in intensity order: id 4 feels stronger than id 5, so the app ships a hand-ranked ladder rather than a numeric one.

You cannot film a feeling

There is no demo video, and there cannot be one: a video of this app is a hand resting on a trackpad. The site shows the actual pulse train instead, drawn live from the same numbers the app sends to the hardware.

What it does

Features

Six cats. House Cat is the measured one. The others differ in pitch, breath and restlessness, from Kitten to Old Tomcat to Making Biscuits.
It has moods. Rest a hand and it usually purrs. Sometimes it looks at you and decides not to, then sulks. Poke it while it sulks and the sulk gets longer.
It has a life. A different temperament each day, a trust that deepens over three weeks of use, rare unexplained zoomies, and small gifts left in the menu bar.
It has manners. Automatic purring pauses whenever a microphone or camera is live, so it never buzzes through a call. Lid shut on an external display and it naps.
Record your cat. Ten seconds of your own cat, analysed on device, and the trackpad learns her purr. Nothing is uploaded.
Costs nothing to run. About half a percent of one CPU core while purring, under 3 MB of memory.

Assets

Icon and artwork

The mark is a paw drawn in the same dot grid the app uses everywhere else. Amber is #E89E2B; the background is #262220. Right click to save, or take the bundle.

Download the asset bundle

Background reading, free to quote: Measuring a cat, the full engineering write-up.

Icon at every size, plus these descriptions as plain text.

If you only quote one thing

"It purrs at 25.75 Hz because that is what the cat was doing. The app is not a sound effect, it is an impression of an animal, and the animal was measured."