Chai is a free, open-source Mac utility that keeps your system awake on demand, preventing sleep, screen dimming, and display shutoff without touching your Energy Saver settings.
What is Chai?
Chai is a lightweight menubar app for macOS that holds your machine awake for as long as you need it — whether that's a two-hour download, an overnight render, or a long presentation where you'd rather not babysit the trackpad. It lives in your menu bar, stays out of the way, and does exactly one thing exceptionally well.
The project is fully open-source, maintained on GitHub, and ships via Homebrew Cask, so installing it takes seconds and updating it takes even fewer. There's no sign-up, no telemetry, and no upsell screen — just a small flame icon waiting to be toggled.
What does Chai do best?
Chai's superpower is radical simplicity. One click in the menu bar activates a keep-awake session; another click ends it. The system's actual sleep preferences are left completely intact, so when Chai is off your Mac resumes its normal power behaviour without you needing to reverse any settings.
Where comparable utilities like Lungo or Caffeine add scheduling or duration pickers, Chai stays deliberately minimal. If you've ever reached for Amphetamine and thought "I just want the thing that keeps my screen on, nothing else," Chai is your answer. It runs natively on Apple Silicon and Intel Macs alike, carries a near-zero memory footprint, and doesn't require any system extensions or accessibility permissions.
Is Chai free?
Yes — Chai is completely free to download and use. It's an open-source project released on GitHub, meaning you can inspect every line of code, fork it, or contribute to it. There are no in-app purchases, no Pro tier, and no subscription. For a utility this focused, the zero-cost model feels entirely appropriate.
Who should use Chai?
Chai is the right tool for anyone who periodically needs their Mac to stay awake but doesn't want a heavyweight utility cluttering their system. Power users doing long compiles, large file transfers, or unattended backups will find themselves toggling it several times a week. Presenters and teachers who run slide decks from a laptop will appreciate being able to flip it on before a session without digging into System Settings.
If you're already using Lungo, Amphetamine, or the built-in Focus/Display modes for this job and those feel like overkill, Chai is worth a look. Conversely, if you need timed sessions, scheduled wake windows, or AppleScript hooks, the more fully-featured Amphetamine is a better fit — it's also free and excellent, just substantially more complex.
How does Chai compare to Lungo and Caffeine?
Lungo, from the prolific Sindre Sorhus, adds duration presets and a polished UI; Caffeine (the classic) is similarly spartan but largely unmaintained. Chai sits closer to Caffeine in philosophy — pure toggle, no extras — but is actively maintained on GitHub, ships with Apple Silicon support out of the box, and integrates cleanly with Homebrew for update management.
Amphetamine is the feature-maximalist end of this spectrum: triggers, schedules, battery thresholds, AppleScript. It's free on the App Store and genuinely powerful. But "powerful" and "what I need right now" are often different things. Chai earns its place precisely because it refuses to become Amphetamine.
What are the best Chai alternatives?
For a direct comparison:
- Lungo — polished, duration-aware, Sindre Sorhus quality. Free with optional tip.
- Amphetamine — full-featured, schedulable, free on the Mac App Store.
- Caffeine — the original minimal toggle; largely unmaintained as of writing.
- macOS Focus modes + display settings — built in, but clunky to toggle quickly.
If you want something you install once, never think about, and trust to work on any Mac you run it on, Chai belongs at the top of that list.
