Does this Mac app run natively on Apple Silicon?
Every Mac sold since 2020 runs Apple Silicon, and an app can be built for it, built for Intel only, or built for both. An app with an arm64 build runs directly on the processor. An Intel-only app still runs, translated by Rosetta 2, which costs some performance and a slower first launch.
What the architectures mean
arm64 is the Apple Silicon build — the M-series processors in every current Mac. x86_64 is the Intel build. An app listing both is a universal binary: one download containing both, with the right one used automatically.
An Intel-only app is not a broken app. Rosetta 2 translates it on first launch and it then runs at a fraction below native speed for most work, which for a text editor or a utility is imperceptible. Where it shows is sustained processor work, and in battery life.
There is a narrower case worth knowing about: an Intel-only app cannot load an arm64 plug-in, and vice versa. If you depend on plug-ins, the app and its plug-ins have to agree.
How we read it
Two sources, and the listing says which. Where we have opened the app bundle, the architectures come out of the Mach-O headers of the binary itself, which is as direct as this gets. Otherwise the reading comes from what the app's Homebrew cask declares it supports.
A Homebrew declaration is the developer's or the maintainer's statement rather than a reading of the binary, so it is weaker evidence — accurate in the ordinary case, and capable of lagging a release.
What it does not mean
An arm64 build says nothing about whether the app is any good on Apple Silicon, only that it is built for it. An app can be native to the processor and still slow.
A blank means we have neither opened the bundle nor found a declaration, which is not the same as Intel-only. Most Mac apps under active development ship arm64 builds now, so a blank here is far more likely to be a gap in our checking than an app that skipped the last five years.
Questions
Will an Intel-only Mac app still work on an M-series Mac?
Yes. Rosetta 2 translates Intel apps automatically, with a slower first launch and some performance cost afterwards. The exception is plug-ins, which have to match the architecture of the app loading them.
How do I check whether an installed app is Apple Silicon?
Open Activity Monitor and look at the Kind column while the app is running. It reads Apple for a native build and Intel for one running under Rosetta.
What is a universal binary?
A single app containing both the Apple Silicon and Intel builds. macOS picks the right one, so the same download works natively on either kind of Mac.