Support

Have a question or running into a problem? We're happy to help.

Email us
support@denapp.xyz
We typically reply within 1–2 business days. Including your device model and app version helps us help you faster.

Frequently asked questions

What is CDL Prep?

CDL Prep is a study app for the U.S. Commercial Driver's License (CDL) knowledge test. It offers 300+ practice questions with explanations, timed mock exams, a spaced-repetition review mode, and translation of content into your language. It is an independent study aid and is not affiliated with any state DMV or testing agency.

Is the app free? What is CDL Pro?

You can start for free. CDL Pro is an optional subscription that unlocks all practice sets and removes the free translation limit. You can explore the app and decide whether to upgrade. Pricing and any free trial are always shown before you buy.

How do I restore a previous purchase?

Open Settings in the app and tap Restore Purchases. Make sure you're signed in with the same Apple ID or Google account you used to subscribe.

How do I cancel my subscription?

Subscriptions are managed by the app store, not inside CDL Prep:

iPhone/iPad: Settings → tap your name → Subscriptions → CDL Prep → Cancel.
Android: Play Store → profile → Payments & subscriptions → Subscriptions → CDL Prep → Cancel.

Cancel at least 24 hours before the renewal date. Uninstalling the app does not cancel a subscription.

How do I get a refund?

All purchases are processed by Apple or Google, so refunds are handled through them:

Apple: visit reportaproblem.apple.com.
Google Play: request a refund from your Play Store order history.

How do I change the language or translate a question?

Set your language during onboarding or anytime in Settings → Language. While studying, tap the translate option on a question or explanation to see it in your native language. Translations need an internet connection; everything else works offline.

Does the app work offline?

Yes. The entire question bank is stored on your device, so you can practice, take exams, and review without a connection. Only the translation feature requires internet.

Which states are supported?

CDL Prep uses a national question bank that applies across U.S. states. Selecting your state sets the correct official handbook reference for you. Practice questions are for study only and may differ from the exact questions on your state's exam — always follow your state's official CDL handbook.

How is my data handled, and how do I delete it?

CDL Prep works without an account and does not collect your name, email, or location. Your progress stays on your device and is removed when you uninstall the app. To delete the anonymous record used for the translation feature, email us at support@denapp.xyz. See the full Privacy Policy for details.

I think a question or answer is wrong.

Thanks for helping us improve. Email support@denapp.xyz with the test name and the question, and we'll review it.