Abendrot

The macOS app for your circadian rhythm

Grounded in peer-reviewed light research, Abendrot warms your displays around your local sunset.
Free and open source. No ads, no in-app purchases, no paywall.

_{Built in the open · abendrot.app · MIT licensed}

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Abendrot is a native macOS menu-bar app that warms each display using the methods available on that Mac. When direct display warming is unavailable, it can fall back to a screen tint.

Install

Download the signed, notarized .dmg from abendrot.app/download, or from GitHub Releases.

Requires macOS 14 "Sonoma" or later. Universal for Apple silicon and Intel.

Homebrew

brew install --cask matthewrball/tap/abendrot

The cask installs the same signed, notarized release and adds the bundled abendrot command-line tool to your PATH.

Abendrot is free and open source under the MIT License. If it is useful to you, please star the repository.

Why Abendrot

• Per-display warming. Abendrot detects the methods available to each display and uses direct warming or a screen tint where supported.
• Reveal True Color. Hold a global hotkey to temporarily lift warmth; release it to restore warmth.
• Scriptable & AI-controllable. An abendrot CLI drives the running app from your terminal — or from an AI assistant like Claude Code, Codex, or Cursor. Read live state as JSON, set warmth, trigger a reveal. (see Scripting & AI control)
• Health is the context; reliability is the proof. Abendrot gives you warmer, lower-blue light in the evening, and links the circadian research instead of making medical claims.
• Local and auditable. MIT-licensed, no telemetry, no account. Settings and usage statistics stay on your Mac; only update checks contact GitHub.

WarmthKit

Warmth that adapts to every display. WarmthKit is Abendrot's open-source display engine. It keeps built-in and external screens warm through sleep, wake, and reconnects, and falls back to a screen tint instead of silently doing nothing when direct warming is unavailable.

Scripting & AI control

Abendrot ships a command-line tool, abendrot, that drives the running app — so you can script screen warmth from a shell, a keybinding, a launchd/cron job, or hand the same commands to an AI coding assistant like Claude Code, Codex, or Cursor. It's the same auditable engine the menu bar drives, now with a command surface you can read and automate.

abendrot set warmth 0.8        # warm the screen to 80%
abendrot status --json         # read live state as JSON — pipe it anywhere
abendrot reveal --hold 10      # momentary true-color peek, then ease back

Trust boundary, stated honestly: abendrot talks to the app as the same macOS user, in your local session, and changes visual state only — no network listener, no privileged helper. An AI assistant "controlling Abendrot" is just running the same abendrot command you could type yourself, and it can't reach any further than you can. The binary ships inside the app bundle; the Homebrew cask symlinks it onto your PATH.

Every command supports --json, with scriptable exit codes. See AGENTS.md for the complete CLI and agent-control reference.

Research and comparisons

• Research and supporting references
• How Abendrot compares with Night Shift and f.lux

General wellness, not medical advice. Abendrot reduces evening blue-light exposure; it is not a medical device and makes no claim to treat or improve any condition.

Tech

Native Swift 6 (SwiftUI + AppKit), macOS 14 "Sonoma" or later, distributed as a universal Apple silicon + Intel app. Tahoe uses native Liquid Glass; Sonoma and Sequoia use the built-in material fallback. No Electron, no bundled runtime. The warmth engine lives in a standalone, unit-tested Swift package (WarmthKit); the app is a small menu-bar agent; the abendrot CLI is a separate thin client that talks to the running app.

Privacy

No telemetry. No analytics SDK, account, or identifiers. Settings and usage statistics stay on your Mac; only update checks contact GitHub. See PRIVACY.md.

Contributing

Issues and pull requests are welcome — bug reports from real display setups are especially valuable, since the whole point is reliability on hardware we can't all test on. See CONTRIBUTING.md for the local build and test setup. Security disclosures: SECURITY.md.

License

MIT © Matthew Ball. Free and open source. If Abendrot is useful to you, you can support its maintenance via GitHub Sponsors.

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_{Warm into the evening.}