Check the acquisition promise
Read the store headline, screenshots and description. What problem is the app promising to solve?
Study the storefront ↗MastrAPI · iOS
Explore the ad evidence, study the storefront, and build your next acquisition hypothesis.
01 / Creative research
Read the store headline, screenshots and description. What problem is the app promising to solve?
Study the storefront ↗Explore apps with direct store-link matches. Compare their hooks and formats without assuming the same approach works here.
Browse observed advertisers ↗Store rankings and revenue estimates describe market context. They do not establish ad spend, conversions or ROAS.
Review the market context ↗02 / Storefront & product
Study the product story and store experience behind the acquisition funnel.
03 / Market context
Keep revenue, downloads and store rankings separate from advertising performance.
App is simple and intuitive to use. It’s responsive and easy to read and answer questions. But the question bank seems small. I’ve gotten the same question twice in a 20 question quiz. Twice now I’ve had the ‘daily question’ be wrong because the task was to interpret an ABG and to differentiate between partially compensated and uncompensated but the question only contained a pH and a CO2. The rationale told me to look at the HCO3 that of course wasn’t listed in the question. Am I meant to calculate the HCO3 from the other two numbers myself? If so, put that in the rationale.
I paid $99 for the lifetime fee. I’ve tried to reach out several times via email. No response. First the APP would not open off WIFI. No response. Then I kept reloading and now I get the same 20 questions for the past two weeks. The random questions are different but that is 40 questions. So in all only 65 questions in the ADULT CCRN for $99?. So. You just responded that you answer all responses if I use the contact us button on your APP. I have tried that several times already. I checked trash, junk and inbox. Nothing from your site. Hey. 4/27. I would like to thank you for getting back in touch with me several times and rectifying the situation. I really appreciate your app. I love that it gives you a rationale right away if you want it. 4/28. Okay here we go again…The questions are starting to repeat again. Same twenty questions as yesterday no wonder I got 100% Apparently the lifetime $99 purchase is not working correctly. I didn’t download off wi fi at first, then it did, now it keeps giving me the same questions.
Excited to announce that I have passed the CCRN exam! I have practiced 6 wks 8-12 hrs daily. The most difficult parts of the exam for me were memorizing the ventilator settings and pulmonary topics. This app covers everything and helps you to achieve the desired result!
Updated for the 2026 CCRN exam cycle — new question sets, refreshed rationales, and up-to-date exam tips keep your study plan current. Pass your CCRN...
| Name | Price | Type |
|---|---|---|
| Monthly access by subscription | $24.99 | Monthly |
| Lifetime access | $99.99 | One-time |