Caffeine vs Amphetamine vs Browser-Based Jiggler: Which to Use
Three popular ways to keep a computer awake, three completely different trust models. The right choice depends less on features than on one question: what are you actually allowed to do to this machine?
The contenders
Caffeine is a generic name for a family of small keep-awake utilities. On Windows the best known is a tiny freeware app that simulates a harmless key press every minute; on macOS the original Caffeine app has largely been superseded by the built-in caffeinate command, which does the same job with nothing installed.
Amphetamine is a free, well-maintained macOS app from the Mac App Store. It is the most capable option here, with triggers, sessions, and conditions like "stay awake while this app runs" or "while the battery is above 30%".
A browser-based jiggler is a web page showing a moving pattern. You put a phone under an optical mouse and the mouse reports genuine movement. Nothing is installed on the computer at all.
Head to head
| Caffeine-type app | Amphetamine | Browser-based | |
|---|---|---|---|
| Platform | Windows, Linux, older macOS | macOS only | Any, via a second device |
| Cost | Free | Free | Free |
| Installation | Required | Required | None |
| Admin rights | Often | No (App Store) | No |
| Works on a locked-down machine | Frequently blocked | Blocked if the Store is disabled | Yes |
| Prevents display sleep | Yes | Yes | Yes |
| Prevents idle lock | Sometimes | No | Yes |
| Keeps chat status active | Sometimes | No | Yes |
| Moves your cursor | No (sends keystrokes) | No | Yes |
| Extra hardware | None | None | Phone + optical mouse |
The rows that actually decide it
"Prevents idle lock" and "keeps chat status active"
These two rows are the same distinction wearing different hats, and they are the most misunderstood part of this whole topic.
Amphetamine and caffeinate use the operating system's official "keep awake" assertion. They tell macOS that something needs the display or the system on. What they do not do is generate input. So the idle timer keeps ticking, and anything reading that timer - the lock policy, Teams, Slack - carries on as if you had left.
Jigglers, whether hardware or browser-based, do the opposite: they produce real input events, which resets the idle timer, which affects everything downstream of it.
So: if your screen goes dark, use an assertion-based tool. If you get a password prompt or your chat status goes yellow, you need input. Choosing the wrong category is why people report that a tool "did nothing".
Caffeine-type apps sit awkwardly in the middle
The classic Windows Caffeine app sends a key press - usually F15, a key that exists in the scancode table but on no real keyboard - every 59 seconds. That is input, so it resets the idle timer, so it often does prevent the lock and the away status.
"Often" rather than "always", because synthetic input is generated with an API that some enterprise security software distinguishes from hardware input. On a managed machine it may be ignored, or flagged. This is the practical reason the category has a mixed reputation.
The download risk
Amphetamine comes from the Mac App Store and is sandboxed and reviewed. caffeinate is part of macOS. Both are safe by construction.
"Caffeine for Windows" is a different situation. The original is a legitimate 40 KB freeware tool, but it is hosted on aggregator sites that wrap downloads in adware installers, and there are copies with the same name and different contents. If you use it, get it from the author's own page, check the file size is what you expect, and be suspicious of any version that ships an installer at all.
Which should you use?
macOS, you can install things: Amphetamine. It is free, reviewed, actively maintained, and its trigger system means you can set it once and stop thinking about it. If you would rather install nothing, caffeinate -d in Terminal does 90% of the job.
Windows, you can install things: PowerToys Awake, not Caffeine. It is Microsoft-published, open source, uses the documented API, and carries none of the download risk.
Any platform, you cannot install anything: a browser-based jiggler. It is the only option in this comparison that changes nothing on the computer, and the only one that reliably handles idle locks and presence indicators. The cost is that it occupies a phone and needs an optical mouse.
You need it unattended, indefinitely, with no phone tied up: a hardware jiggler is the pragmatic answer, with the USB policy caveats that come with it.
Combining them
Nothing stops you using two. A common pairing on a work laptop: PowerToys Awake or caffeinate to keep the display on during a long job, plus a browser jiggler on a phone for the stretches where an idle lock would otherwise interrupt you. They operate through different mechanisms and do not conflict.