The export menu with a GIF-shaped hole
Open File, Export As in QuickTime Player and count the options: 4K, 1080p, 720p, 480p, Audio Only, and, when a device is attached, an iOS-friendly variant. Every one of them is a video. There is no animated GIF anywhere in the app, and there has not been for years.
It used to be there. QuickTime Player 7 Pro, the paid unlock from the 2000s, carried an Export choice called Movie to Animated GIF, which is how a generation of Mac users made their first loop. QuickTime 7 was 32-bit, and macOS Catalina stopped running 32-bit apps in 2019, so the feature went where 32-bit features go. Nothing in modern QuickTime replaced it. That gap is the entire reason this page exists, and closing it takes a browser tab rather than a purchase.
Let QuickTime do the parts it is genuinely good at
Credit where it is owed: as a capture tool, QuickTime Player is excellent and free and already installed. File, New Screen Recording hands off to the same on-screen controls as Command-Shift-5, so you can draw a region and record only that. New Audio Recording and New Movie Recording do what they say. And the lesser-known one worth knowing: plug an iPhone or iPad into a Mac by cable, choose New Movie Recording, and pick the device as the camera source. You get a clean recording of the phone's own screen with no capture app on the phone at all.
Use it for all of that. Then bring the .mov here for the part it never learned. Getting a Mac screen recording into a postable loop is the same job the screen recording guide covers end to end, whatever recorder produced the file.
ProRes is the one file that will argue with you
A .mov is a container, and what is inside it decides whether anything can open it. Screen recordings and ordinary iPhone video are H.264 or HEVC, and those load without ceremony. ProRes is a different story. Final Cut exports it, iPhone Pro models can shoot it, and no browser ships a ProRes decoder, so a ProRes .mov will simply refuse to open here.
The fix takes one pass through the app you already have: File, Export As, 1080p writes an H.264 movie that behaves normally. Your ProRes master stays untouched. There is a size argument for doing this anyway, since ProRes 422 HQ at 1080p runs on the order of 200 megabits per second, which puts a single minute well over a gigabyte, and this tool guards against files past roughly 500 MB to protect your browser's memory. HEVC is the softer version of the same issue, since decoder support varies by browser and machine; the HEVC guide covers the one-time conversion when a file stalls.
The trim QuickTime gives you, and the trim it doesn't
QuickTime's Command-T trim is a yellow bar with two handles dragged by eye at whatever scale the window happens to be, and when you save, you are writing a new movie. It is a fine rough cut. It is not a frame-level decision, and it changes your footage.
The trim here works differently in both respects. Click a handle to focus it and each arrow key press moves the edge exactly one frame, which is the difference between a loop that snaps closed and one that stutters at the seam. And your .mov is never modified, because it is never written to: the file is read into the page, the output is a brand new GIF, and the original sits on disk in the state QuickTime left it. Frame-accurate and non-destructive, which is a combination the Player itself has never offered.
Mac-born file, any machine you like
A .mov is not a Mac-only object, whatever the icon suggests. Chrome or Firefox on Windows, a Chromebook, a Linux desktop: if the browser can play the file, it can convert it, so a recording AirDropped to a colleague converts on whatever they happen to own. Mac users get one extra convenience, which is that Safari is a first-class citizen here and the Mac page lays out the whole desk-side workflow.
The privacy math is simpler than it sounds. QuickTime never asked to see your screen recording, and neither does this. The difference is that one is an app you installed and the other is a page you can close, and the reason it can make that claim is architectural rather than legal: the decode, the trim, and the GIF encode all happen in the tab, so there is no upload to audit. Bring the .mov over and see how fast it goes.