Keron

Download

Get Keron

Free, and about two minutes to set up. The only thing Keron asks for afterwards is the Accessibility permission — without it macOS won't let any app see the notification banners it draws.

Download Keron

Version 1.0  ·  macOS 27.0 or later  ·  Apple silicon and Intel  ·  2.9 MB

Requirements

Before you start

Operating systemmacOS 27.0 or later
Permission neededAccessibility, granted in System Settings
SigningThe build is not notarized by Apple, so the first launch needs one extra step — see below
PriceFree, no account, no trial
DownloadKeron.zip — 2.9 MB (3,016,289 bytes)
SHA-256396835b8d5bc0d52d1429bb6739a4ab8f8c4dc2589b9daa27c81b426d53de43f

Setup

Installing Keron

  1. Download and unzip

    Grab the latest build using the button above and unzip it if your browser hasn't already.

    Since this build isn't signed by Apple, you may want to confirm you got the file intact. Run this and check it against the SHA-256 above: 

    shasum -a 256 ~/Downloads/Keron.zip

  2. Move it to Applications

    Drag Keron.app into your /Applications folder. Keron needs to live in a stable location, because macOS ties the Accessibility permission to the app's path — moving it later means granting the permission again.

  3. Open it the first time

    This build isn't notarized by Apple, so a plain double-click will be refused. Instead right-click Keron.app and choose Open, then confirm in the dialog. You only have to do this once.

    If macOS still refuses, clear the quarantine flag from Terminal and try again: 

    xattr -dr com.apple.quarantine /Applications/Keron.app

  4. Grant Accessibility

    Keron asks for this on first launch. If you missed the prompt, open System Settings › Privacy & Security › Accessibility, then switch Keron on. There's no need to restart it — the engine starts the moment the permission lands, and the warning banner at the top of the window disappears on its own.

  5. Send yourself a test banner

    In the editor, hit Send Test Notification. You should see Keron's own banner appear wherever you've placed it. From here, drag the elements around until it looks the way you want.

Why Accessibility? macOS has no public API for restyling notification banners. Keron uses the Accessibility API to observe the system's Notification Center process, read each banner's app name, title, message and icon, and draw its own overlay in place of the original. There is no other way to do it, and it is the only permission Keron asks for. See exactly what it does with that access.

Removing it

Uninstalling

Keron has no installer and leaves very little behind. To remove it completely:

  • Quit Keron from its menu bar icon, then drag Keron.app to the Trash.
  • Delete ~/Library/Application Support/Keron — this holds any custom sounds and background images you imported.
  • Clear its saved settings by running defaults delete com.nimaigoswami.Keron in Terminal.
  • Optionally remove the leftover entry in System Settings › Privacy & Security › Accessibility.

If you'd rather keep the app but start over, Reset All Settings inside Keron restores every default without touching anything on disk.

Something not working?

The support page covers the common cases — banners not being restyled, the wrong display, Focus modes, and the Gatekeeper warning above.

Go to support