My side project — a habit tracker built for ADHD adults, which is a thing I needed personally, which is the only reason side projects ever ship — hit TestFlight in March. The app did what it promised. The problem was the storefront. My App Store screenshots were literal iOS simulator grabs: no device frame, no captions, no context, just a screen floating in white like a hostage photo. I knew that was costing me installs. I got quotes for a five-screen set: $400 on the low end, $800 on the high end. My design budget was, generously, a rounding error above zero.
One sentence per screen
The App UI Hero Screen — From One Feature Sentence to a Pitch-Ready Mockup prompt is built around exactly the input I had: a sentence per feature. I ran it five times, once per App Store slot. The only thing I changed between runs was feature_description. The primary_color stayed #5E4AE3, the platform stayed iOS, the aspect ratio stayed 9:16. Nano Banana Pro turned each sentence into a framed, lit, native-looking screen in around 40 seconds. The SF Pro type read correctly, the status bar looked like a real iPhone, and the device frame had a soft contact shadow that made it feel photographed instead of pasted.
The first run taught me to write a better sentence
My first feature_description was greedy — I described basically the whole app in one screen, and the hero came back as a busy dashboard, exactly the failure mode the prompt warns against. So I edited my input to be one idea: 'a single large weekly streak ring with one motivational line beneath it.' Run two was clean and confident. That's the real lesson: the prompt is good, but it rewards you for describing ONE thing per screen. The FAB matched my brand purple precisely when I fed the hex code instead of writing the word 'purple,' which the model interprets with the confidence of a toddler picking crayons.
The platform conventions I'd have gotten wrong by hand
Here's a detail I didn't appreciate until it saved me: the prompt bakes in platform conventions, and getting those right is exactly the thing a non-designer fumbles. iOS doesn't have a floating action button; that's an Android Material pattern. The status bar layout, the tab bar at the bottom, the SF Pro type feel — these are the tiny signals that make a screenshot read as 'a real iOS app' versus 'a mockup made by someone who's never used an iPhone.' Because I set platform to iOS, Nano Banana Pro used a bottom tab bar instead of an FAB and a native-looking status bar, and the screens passed the sniff test instantly. If I'd built these in a generic template I'd have absolutely shipped an Android FAB on an 'iPhone' and looked like an amateur to the exact App Store reviewers and users I was trying to impress.
App Store review, for the record, does look at your screenshots — not for design quality, but for whether they misrepresent the app. Because each of mine showed a real feature described in plain language, there was nothing to flag. They were polished AND honest, which is the only combination that survives both the reviewer and the actual user who downloads expecting what they saw.
- Five App Store screenshots produced for $0 against a $600 quote
- Total time: 47 minutes including the iteration where I learned to write shorter feature sentences
- App was approved and went live with these exact screens
- The same mockups now anchor my landing page — one asset set, two jobs done
Honest about what this is and isn't
This will not replace a senior product designer who understands your information architecture. If you're a funded team, hire the human. But if you are one tired person trying to get a real thing across the App Store finish line, this is the difference between shipping and stalling out at 95% because the storefront looks like a prototype. The mockups are good enough that nobody on my landing page has asked whether they're 'real' — they just see a polished product, which is the whole game at the top of the funnel.
I keep this one premium in my own library because it's the prompt I'd genuinely have paid that $600 for. When I need to put one headline metric on a slide instead of a whole screen, I switch to my Presentation Hero Slide — Turn One Stat Into a Boardroom Visual prompt. Grab the App UI Hero Screen — From One Feature Sentence to a Pitch-Ready Mockup prompt on Prompt Dock and run it on your own feature list — one sentence per screen, your real hex code, and you've got a storefront that looks like you had a budget.