The short version. Lumen is provided as-is. You can use it for personal, non-commercial use. If you buy Lumen Pro through Apple, the purchase is non-refundable except as Apple's policies provide. We're not liable for any damages from using the app — but we'll do our best to keep it working and improve it over time.
1. Agreement
These Terms of Use are an agreement between you ("user") and Doku Studio ("we", "us") governing your use of the Lumen iOS application and any in-app purchases. By installing or using Lumen, you agree to these terms. If you don't agree, please don't use the app.
Apple's Licensed Application End User License Agreement (the "Apple EULA"), available at apple.com/legal/internet-services/itunes/dev/stdeula, also applies to your use of Lumen. Where these terms and the Apple EULA conflict on a particular point, the more user-protective term controls.
2. License
Subject to these terms and the Apple EULA, we grant you a limited, non-exclusive, non-transferable, revocable license to install and use Lumen on Apple-branded devices that you own or control, for your personal, non-commercial use.
You may not:
- Reverse-engineer, decompile, or disassemble Lumen, except where prohibited by law to be enforceable.
- Remove or alter any proprietary notices.
- Sub-license, sell, rent, or lease the app.
- Use the app to violate any law or to harm others.
3. Lumen Pro (in-app purchase)
Lumen offers a one-time, non-consumable in-app purchase ("Lumen Pro") that unlocks additional features. The price is shown on the paywall in your local currency, set by Apple.
- Purchases are processed by Apple. Payment is charged to your Apple ID.
- The Pro entitlement is tied to the Apple ID you used to purchase it. Family Sharing is supported as configured by Apple.
- Refunds are handled by Apple per their refund policy: Request a refund for apps or content that you bought from Apple.
- Restoring a previous purchase is available in Settings → Restore purchase inside the app.
Pro features in effect at the time of purchase will remain unlocked. If we change the set of Pro features in a future version, your previous purchase remains valid for the features it covered, plus any additions made to the Pro tier going forward at no extra cost. We do not retroactively remove features from the Pro tier.
4. Hardware and safety
Lumen drives the rear camera LED ("flash") and screen brightness. Do not use Lumen:
- While driving, operating heavy machinery, or other situations where bright light or screen attention is unsafe.
- To intentionally trigger seizures or otherwise harm anyone with photosensitive conditions. The strobe and SOS effects produce rapid flashing.
- For medical, emergency, or signaling purposes where reliability is critical. Lumen is a consumer utility, not certified safety equipment.
iOS may turn off the LED when the app is backgrounded. This is a system limitation, not a Lumen failure.
5. Intellectual property
Lumen, the Lumen name, the Doku Studio name, and the visual design of the app are owned by us. Apple frameworks, fonts, and SF Symbols are owned by Apple. PostHog SDK is owned by PostHog. None of these are licensed to you beyond what is necessary to use the app.
6. Disclaimer of warranties
Lumen is provided "as is" and "as available" without warranties of any kind, either express or implied, including but not limited to merchantability, fitness for a particular purpose, and non-infringement. We do not warrant that the app will be uninterrupted, error-free, or perfectly compatible with every iOS version or device.
7. Limitation of liability
To the maximum extent permitted by law, Doku Studio is not liable for any indirect, incidental, special, consequential, or punitive damages arising out of your use of Lumen, including but not limited to loss of data, loss of revenue, or device damage. Our total liability for any claim relating to Lumen is limited to the amount you paid for Lumen Pro, or, if you have not made any purchase, USD $0.
Some jurisdictions don't allow this limitation. In those jurisdictions, our liability is limited to the smallest amount permitted by law.
8. Termination
You may stop using Lumen and delete it at any time. We may also discontinue Lumen, in whole or in part, at any time, for any reason, with reasonable notice when feasible.
9. Changes
We may update these terms when the app changes. We'll bump the effective date at the top and surface a notice in the app on the next launch for material changes. Continued use after changes means you accept the new terms.
10. Governing law
These terms are governed by the laws of the Socialist Republic of Vietnam, without regard to conflict-of-laws principles. Where mandatory consumer protection laws of your country of residence give you more rights, those laws apply.
11. Contact
For questions or concerns about these terms, email hello@dokustudio.com.