Yes. MaxNit uses the same private brightness pathway macOS itself uses to light up HDR content — it just makes that headroom available all the time. Running brighter draws a bit more power and runs slightly warmer, exactly as HDR video does.

A brighter screen always uses more energy, so pushing toward Max XDR will shorten battery life while it's cranked. Dial the slider back down — or quit MaxNit — and you're right back to stock behavior.

The brightness keys stop at the standard SDR ceiling. MaxNit unlocks the extra XDR/HDR headroom above that line and applies it to everything on screen, not just HDR media.

It's built for Apple's Liquid Retina XDR displays — the built-in screen on MacBook Pro and the Pro Display XDR — where the extra brightness headroom lives. Ordinary SDR monitors have no extra headroom to unlock.

Completely. No price, no account, no telemetry. MaxNit is open source under the MIT license — read the code, build it yourself, or contribute on GitHub.