I make Shiny, so take this comparison with that in mind. I've tried to write it honestly: where OnyX is the better choice, I'll say so. OnyX is a genuinely excellent piece of free software, and it deserves to be described accurately rather than knocked down to make Shiny look good.
At a glance
| Shiny | OnyX | |
|---|---|---|
| Price | $4.99 once, forever | Free (donationware) |
| Job | Memory clearing | Maintenance toolkit |
| UI | Modern menu bar | Tabbed app, dated |
| Workflow | One click | Open app, navigate tabs, tick checkboxes, click execute |
| Memory cleaning depth | Deep (orphaned helpers, inactive memory, idle apps) | Light (cache clearing as part of broader maintenance) |
| Lives in menu bar | Yes | No |
| Made by | THEODOREHQ | Titanium Software (since 2003) |
What OnyX actually does (it's broader than memory)
Most people who search "OnyX memory cleaner" have the wrong mental model of what OnyX is. It is not a memory cleaner. It is a Mac maintenance and configuration tool that happens to include some cache-clearing functions that touch memory indirectly.
Here is what OnyX actually does: it runs the periodic maintenance scripts that macOS normally schedules automatically (daily, weekly, and monthly). It clears system and application caches. It can rebuild the Spotlight index after it gets corrupted or after a major update. It exposes hidden system preferences that Apple doesn't put in System Settings, things like Finder tweaks, Dock animations, and screenshot format options. It shows you system logs and basic hardware info. It has an automation tab where you can chain multiple maintenance tasks together and run them in one go.
That is a lot. And all of it is free. Titanium Software has kept OnyX updated for every major macOS version since 2003, including Apple Silicon, which is a remarkable track record for a free tool.
The downside is the interface. OnyX's UI hasn't changed much in a decade. It is a tabbed app with rows of checkboxes, dropdowns, and buttons. If you know what you're looking for, that's fine. If you don't, it can feel opaque and slightly intimidating. "Verify the structure of the startup disk" sounds more alarming than it is.
Where OnyX wins
It is free. There is no version of this comparison where I pretend that $4.99 beats free. If your only goal is occasional Mac maintenance, OnyX costs nothing and does more than Shiny in terms of breadth.
Maintenance scripts. OnyX runs the periodic Unix maintenance scripts that macOS normally runs in the background at set intervals. If your Mac is often asleep overnight when those scripts would run, they can fall behind. Opening OnyX and running them manually catches up. Shiny doesn't do this at all.
Spotlight rebuild. After a major macOS update, or if Spotlight search starts behaving oddly, a Spotlight index rebuild usually fixes it. OnyX makes this straightforward. Again, Shiny has no equivalent.
Hidden preferences. OnyX exposes system settings that Apple hides. Want to change where screenshots save, how Dock animations behave, or what information the menu bar shows? OnyX surfaces those options cleanly. Shiny is a memory tool - it doesn't touch any of this.
Twenty-three years of trust. Titanium Software has been shipping OnyX since 2003. That longevity means a huge body of user experience, thorough macOS compatibility testing, and a developer who clearly cares about the tool. Shiny is a newer, smaller product. My quality bar is high, but it is not two decades of accumulated trust.
Where Shiny wins
It is purpose-built for memory. Shiny goes deeper on memory than OnyX does. It closes orphaned helper processes left behind when apps quit, releases inactive memory sitting idle, and pauses apps you haven't used in a while. OnyX clears caches as part of maintenance, which frees some memory indirectly - but memory is not its focus and the depth is not comparable.
One click, from anywhere. Shiny lives in your Mac's menu bar. When your Mac feels sluggish and the memory pressure gauge edges into orange, you click the Shiny icon. That's it. You don't open an app. You don't navigate to a tab. You don't tick checkboxes and click execute. The whole thing takes two seconds. OnyX requires you to open it, find the right section, configure what you want, and then run it.
It is always there. Because Shiny lives in the menu bar, it is available instantly whenever you need it. OnyX sits in your Applications folder waiting to be opened. For something you want to do regularly - like clearing memory when your browser has been open for eight hours - the menu-bar presence matters a lot in practice.
No learning curve. OnyX has a lot of options, and some of them sound technical. Most are safe, but "rebuild the databases of Launch Services" is not an instruction that means much to a non-technical Mac owner. Shiny has one button. You press it, memory gets freed, it tells you how much. There is nothing to misconfigure.
Should you use both?
This is actually the honest answer for a lot of people: yes.
OnyX and Shiny don't overlap in any meaningful way. OnyX handles periodic maintenance - running scripts, clearing deep caches, fixing Spotlight, tweaking system preferences. Most people open it once every few months, after a big macOS update, or when something feels off. It is a deliberate maintenance tool for deliberate maintenance sessions.
Shiny handles a completely different moment: the everyday one where your Mac is slowing down because memory is full, and you want to fix it right now without opening anything or thinking about it. It's a reflex action. Menu bar, click, done.
There is no conflict between them. They don't step on each other's toes, they don't slow each other down, and they address genuinely separate problems. Many power users run OnyX occasionally for the broader maintenance and Shiny daily for fast memory clearing. If you want to keep OnyX installed for free and add Shiny for $4.99, that is a completely reasonable setup.
If you are only ever going to use one, think about which problem you actually have more often. Do you find yourself wanting to run maintenance scripts and rebuild Spotlight? OnyX is excellent and free. Do you find your Mac slowing down from memory pressure and wanting to clear it with a single click from wherever you are? That is what Shiny is for.
You can also compare Shiny against other tools in this space. See Shiny vs CleanMyMac for a comparison with the subscription-based suite option, or read our best Mac memory cleaner for 2026 roundup for a broader look at what's available. If you're wondering whether any of these tools are worth it at all, are Mac cleaner apps actually worth it? gives you an honest answer.