Onyx vs Mainspring: Maintenance or Settings?

Onyx from Titanium Software is one of the best known free Mac utilities, and it has been maintained through every macOS release for over twenty years. It overlaps with Mainspring in one section, so it is worth being precise about where.

What it is

Onyx is primarily a maintenance tool: running periodic scripts, clearing system and application caches, rebuilding databases, verifying the startup disk. Its Parameters section also exposes a good number of hidden preferences. Titanium Software ship a separate build for each macOS version.

Where they overlap

Both can change hidden Finder, Dock and screenshot preferences without the Terminal, and both are built by small independent developers rather than large companies.

Where they differ

• Maintenance. Onyx does it, Mainspring does none at all. No cache clearing, no scripts, no disk verification.
• Undo. Mainspring records every change and gives each one an undo button, with an On now screen listing what is currently enabled. In Onyx you flip a parameter and it is on you to remember the default.
• Versions. Onyx ships a separate download per macOS release. Mainspring is one universal app covering macOS 13 and later.
• Price. Onyx is free. Mainspring is a one-time 29 dollars.

Which should you use?

If you want periodic maintenance and cache clearing, Onyx is the better tool for that and it costs nothing. If your interest is changing settings and being able to walk any of it back, that is what Mainspring is for. Plenty of people run both quite happily.

Every setting here is a one-click, reversible toggle in Mainspring — no Terminal, and an undo button on all of it.