Zazen

mazzarelli@gmail.com (Joey Mazzarelli) — Sun, 27 Sep 2026 00:00:00 -0600

Zazen is a meditation timer for Android, and that is all it is. You pick a length, it gives you a few seconds to settle in, a bell starts the sit, a soft bed of noise plays underneath, and a bell ends it. There are no accounts, stats, streaks, or history, and it never nags you to sit.

Get the app

Android APK: Download Zazen 1.0.0 (~41 MB, Android 7.0 or newer, 64-bit phones)
Google Play: not published. This is a direct download.
iOS: not planned

Point your phone's camera at this to download the APK (~41 MB).

If you want to confirm the file you downloaded is the one I published, its SHA-256 is:

7dab571f7849620cac3079797371bc3d60fd4ad7416774b9b054f8b854fc499d

Install

Android only installs apps from the Play Store until you give permission, and you give it one app at a time.

Open the download link above on your phone.
When it finishes, tap the downloaded file. Android will say your browser (or file manager) isn't allowed to install unknown apps. Tap Settings, turn on Allow from this source, then go back.
Tap Install.
Play Protect may warn you that it doesn't recognize the developer. That's expected, because the app isn't in the Play Store. Tap More details, then Install anyway, if you're comfortable with that.

You can turn Allow from this source back off afterward. It isn't needed for updates.

Updates

Most updates arrive on their own. The app checks for one when it opens and downloads it in the background. The update takes effect the next time you open the app, never in the middle of a sit. You only need to download a new APK when the version number on this page changes. You can also check for an update yourself under settings → Updates.

How a sit goes

Pick a length. 5, 10, 20, or 30 minutes, or your own length from 1 to 120.
Settle in. The screen counts down a short pause (10 seconds unless you change it). Toward the end, a bowl sings as it's rubbed around its rim, so you already know the bell's pitch when it's struck.
The start bell. Once it has rung out, the bed of noise fades in.
Sit. If you like, a soft bell marks the halfway point, or every 5 or 10 minutes.
The end bell. The noise either settles down under the bell or fades out before it, so the bell rings alone.

You can cancel at any point, and the sounds fade out rather than cut off. The sit keeps time by the clock, not by counting seconds, so locking the phone or switching apps doesn't throw it off. The whole sit is scheduled the moment you tap, so you still hear the bells with the screen locked.

The sounds

I really built this to have a clean place to play with sound, and there are no recordings in it. Every sound is synthesized on the phone as it plays, using the Web Audio API (through react-native-audio-api).

The bells are built from a handful of sine waves, one for each ringing tone of a real bell, each fading at its own rate.
The rim is the same tones, plus a band of noise for the friction of the mallet going around the bowl.
The bed comes in three characters:
- drift: pink, green, and brown noise slowly moving around each other and across the stereo field, so it is never quite still. Underneath is an optional binaural beat, which you only hear with headphones.
- pink: plain pink noise, like steady rain.
- brown: plain brown noise, darker, closer to surf.

Nothing ever starts or stops at full volume. Every sound ramps in and out, because a click is the last thing you want to hear ten minutes into a sit.

Settings

A small settings dialog holds everything you can change:

the bells on or off, their volume, and the interval bells
the background noise on or off, its character, its volume, and the binaural beat
how the noise ends: settling under the end bell, or fading out before it
the settling-in pause: 5, 10, or 30 seconds
your own sit length
whether the app closes itself once the last sound fades

Privacy

Zazen doesn't know who you are and doesn't keep track of your sits. The only thing it saves is your settings, in a small file on your phone. There are no ads, no analytics, no crash reporting, and no notifications. The only thing it ever sends over the internet is the check for app updates.

The app is free. It has no paid features, and I have no plans to add any.

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KHTDR – Web-Audio