Mac Ninja

You know the feeling. The fan spins up, the app you're actually using starts to stutter, and somewhere behind it sit a few hundred Chrome tabs you swear you'll get back to. Mac Ninja's pitch is that a slow Mac is usually a crowded one.

It lives in the menu bar and does two things when switched on. It puts idle Chrome tabs to sleep, and it calms background apps that are taking CPU time from the one you're using. The site stresses that it doesn't close your apps or your tabs. The tab you're on stays awake, and so do pinned tabs and tabs playing audio.

There's also a newer feature aimed at AI agents, which open tabs in their own group and leave them behind. With the free Mac Ninja Helper extension for Chrome, the app closes the tabs it saw an agent open once that session has sat untouched for 8 hours.

The headline result is 11.2 GB of Chrome memory freed in one pass, from 26.5 GB down to 15.3 GB. That number is the maker's own. It was measured on the project's test Mac, a 64 GB machine with 479 tabs open across 29 windows in November 2026, and the page adds that your results depend on how you use your Mac.

So treat it as an example from a heavy setup. If your Mac has less memory and fewer tabs, expect a different number.

Yearly is $9.99 and Lifetime is $24.99 once. Both include every feature and cover up to 3 of your Macs. The 7-day trial needs no card, and the terms mention a refund within 14 days of purchase. The app is a direct download as a DMG, with no Mac App Store listing. It runs on macOS 10.15 Catalina or later, on Apple Silicon and Intel, and the download page describes it as signed and notarized by Apple.

According to the privacy policy, last updated November 11, 2026, the app has no account, analytics or tracking, and memory and CPU statistics, settings and the activity log stay on your Mac. Activating a licence sends the licence key, your Mac's name and a hashed device ID to the maker's licence server. During the trial, the app sends the device ID and the trial start date. Tab addresses and titles aren't recorded or sent.

The website itself is different: it uses Google Analytics and the Meta pixel if you accept cookies. The terms give Sweden as the place Mac Ninja is published, and no person or company is named. If you keep Chrome open all day and never close a tab, the free week is an easy way to see what it does on your own machine.