Terms of use

Effective September 28, 2026

OpenTuner is free, has no ads and no purchases, and is provided as is. Use it to tune your instruments. If you build your own version from the source code, give it a different name.

1. Who we are

OpenTuner is a string instrument tuner created and maintained by Guilherme Feitoza, an independent developer. In these terms, "the app" means OpenTuner as distributed through app stores, GitHub Releases and this website, and "you" means anyone who installs or uses it.

2. Accepting these terms

By installing or using the app you agree to these terms. If you do not agree, do not use the app, and uninstall it at any time. Nothing is kept about you after you do.

3. Price and ads

The app is free. It has no ads, no subscriptions and no in-app purchases, and it does not require an account. The goal of the project is to keep it this way for as long as it can be funded and kept in the stores. If that ever becomes impossible, the app may be removed from a store, but it will not be changed to show ads.

4. Open source license

The source code of OpenTuner is available on GitHub under the Apache License, Version 2.0. Your rights to use, copy, modify and distribute the code are the ones granted by that license, and these terms do not limit them.

The fonts included in the app, Fraunces and Manrope, are distributed under the SIL Open Font License 1.1.

5. Name and logo

The Apache License does not grant permission to use the OpenTuner name or logo (section 6 of the license). You can build and publish your own version of the code, but please give it a different name and icon, so that nobody confuses it with the official app. Mentioning that your version is based on OpenTuner is welcome.

6. Using the app

• The app needs access to the microphone to hear your instrument. How that access is handled is described in the privacy policy.
• Tuning is done by turning the tuning pegs of a physical instrument. Turn them gently: overtightening can break a string, and a string that snaps under tension can hurt. Keep your face away from the strings while tuning up.
• Do not use the app, or modified versions of it, in a way that breaks the law or the rules of the store you got it from.

7. No warranty

The app is provided "as is", without warranties of any kind, express or implied, including accuracy, fitness for a particular purpose and uninterrupted operation. Pitch detection depends on your device's microphone, background noise and the instrument itself, and readings can be wrong.

8. Limitation of liability

To the extent permitted by law, the author is not liable for any damage arising from the use of the app or the inability to use it, including broken strings or damage to instruments. Some countries do not allow certain limitations of liability. In those countries, the limitations apply only as far as the law allows, and nothing in these terms takes away rights you have as a consumer.

9. App stores

If you got the app from an app store, that store's terms also apply to your download. On the Apple App Store, Apple's Standard Licensed Application End User License Agreement applies together with these terms. The stores are not responsible for the app or for supporting it.

10. Changes

These terms may change as the app changes. The new version will be published on this page with a new effective date, and the full history is public in the project's repository. Continuing to use the app after a change means you accept the new terms.

11. Governing law

These terms are governed by the laws of Brazil, without prejudice to the mandatory consumer protection rules of the country where you live.

12. Contact

Questions about these terms can be opened as an issue at github.com/guilhermefeitosa66/open-tuner/issues.