Abendrot

Terms of Use

Last updated August 18, 2026.

Abendrot is a free, open-source macOS app built and maintained by an individual developer, Matthew Ball. These terms cover the Abendrot website at abendrot.app and the Abendrot Mac app. Using either means you accept them.

The app is free and MIT-licensed

The Abendrot Mac app and its source code are released under the MIT license. The license text in the repository is the authoritative grant of rights, and it governs if anything here appears to conflict with it. You may use, copy, modify, and redistribute the software on the terms that license sets out, including its requirement to preserve the copyright and permission notice.

Nothing here adds restrictions to the MIT license or takes rights away from it.

No warranty

Abendrot is provided as is, without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose, and noninfringement. This mirrors the MIT license the software is distributed under.

Abendrot changes display color output. Results depend on your Mac, your macOS version, your displays, and how they are connected, and some combinations support direct warming while others fall back to a screen tint. The app is not suitable as a color-accuracy tool for work that requires calibrated output; use Reveal True Color or quit the app when color has to be exact.

To the fullest extent permitted by law, the author is not liable for any claim, damages, or other liability arising from the software or its use.

General wellness, not medical advice

Abendrot is general wellness software. It is not a medical device, and neither the app nor anything published on this website diagnoses, treats, cures, or prevents any condition. The guides in Circadian Notes are general information with sources linked so you can check the reasoning yourself.

Nothing here is a promise about your sleep, your eyes, or your health. If you have concerns about sleep or vision, talk to a qualified clinician.

Downloads and distribution

Official Abendrot builds are distributed through GitHub Releases and the project's Homebrew tap, and the download page links to those releases. Releases are signed with a Developer ID certificate and notarized by Apple.

Builds obtained anywhere else are not published by this project and cannot be verified against its signing identity. If you need to confirm a download, compare its SHA-256 against the digest recorded in the corresponding GitHub release notes.

Using this website

You may read, link to, and quote this site with attribution. Do not use it to break the law, to attempt to gain unauthorized access to it or its infrastructure, or to disrupt it for other people.

Site content is published by the author. Third-party names and trademarks mentioned in comparisons, such as Apple, macOS, Night Shift, and f.lux, belong to their respective owners and are used only to identify those products. Abendrot is not affiliated with, endorsed by, or sponsored by any of them.

Email updates

Signing up for email updates is optional. You can unsubscribe from any update. What is stored and why is described on the privacy page.

Privacy

How the website measures traffic, how optional email signups are handled, what GitHub records about release downloads, and the Mac app's no-telemetry behavior are all covered on the privacy page, which forms part of these terms.

Third-party services

This site and the project rely on services that operate under their own terms and privacy policies, including GitHub for source hosting and release distribution, Cloudflare for website hosting and aggregate analytics, and Google Analytics for website measurement. Update checks in the app contact GitHub. See the privacy page for detail.

Changes

These terms may change as the project changes. The date at the top records the last revision, and continuing to use the website or the app after a revision means you accept the current version.

Contact

The best route for anything about the app, this site, or these terms is a GitHub issue on the project repository. Corrections to the guides are welcome.

Summary