My nephew had to take the CCAT to get an internship. So I built him a practice app in less than a day. He started using it right away, and every time he told me something was missing or annoying or confusing, I fixed it. That app is now Clever Cat Prep, and strangers pay for it.
The CCAT is a speed test
Before I built anything, I had to figure out what the test rewards. The CCAT, the Criteria Cognitive Aptitude Test, is 50 questions in 15 minutes, a mix of math, verbal, logic, and spatial, and almost nobody finishes it. So doing well comes down to gaming the test more than being smart. You have to quickly recognize what kind of question you're looking at, eliminate the wrong choices, know the shortcut, break down how to answer it, and know when to skip it and move on.
The full practice test in the app copies the plain look and the timer of the real CCAT.
And because skipping is a skill, there's a skip map. It ranks every question family by his accuracy and his speed and tells him which ones to skip on test day.
A tight feedback loop
Speed and judgment only come from practice, so the rest of the app is built for drilling. It has about 3,500 original questions in 29 families. You drill one family at a time, timed, and you get instant feedback, with an explanation and a shortcut on every question. Anything you got wrong or flagged comes back later in a review queue. And the app tracks everything, so the progress page shows him which families he's improving on and which ones are slipping.
That's basically the whole pedagogy: drill, see what you did wrong, and try again. It's okay to make mistakes as long as you get feedback quickly.
The AI coach
The feedback that matters most is about him, and that's what the AI coach does. It runs on Claude, and it reads his actual attempts and tells him what to do next, which is the part a human tutor would charge you for.
After a full test he gets a debrief: a headline, his priorities, and the drills to do next.
Each question family has its own coaching, and it remembers the last advice it gave him, so it can tell him what changed since then.
Every question has an AI breakdown with the rule, the notation, and the fast version. And from any debrief, family, or question, he can open a chat and ask the coach.
Built around him
A lot of this came from him. The way the coach talks about his strengths and weaknesses, and the coaching on how to answer, how to eliminate choices, and which shortcuts to use, all started as his feedback. For a while he was the only user, so everything he asked for went in.
He asked me to show the rotation on the spatial questions, the ones where you have to picture a shape turning, and now the shape turns on screen.
He also wanted to practice while he was driving. So I built a voice mode, where he talks through math and logic questions out loud with a coach that talks back.
23 to 39
His first full practice test on the app was a 23. Then he used it for four days, two hours a day, and he got a 39. That's around the 85th percentile.
And he got the internship.
Personal software
It worked because I built it for exactly one person, and I think that's what AI has enabled: really personalized software that you can spin up for yourself or for someone you love.
Before, nobody would have built a voice mode so one person could practice in the car, because it would never have been worth the time. Now I could build it for him.
And then other people found it
Once it worked for him, I figured it could work for anyone else taking the test, so after he was done, I kept working on it until other people could buy it.
It runs on Cloudflare Workers and D1, which costs basically nothing and needs no maintenance. For SEO, I added guides to the different kinds of questions on the test, pages for the companies that use the CCAT, and free tools like a score calculator and a pacing calculator. I also ran a small Google Ads test, but what I was paying to get each customer didn't make sense, so I turned it off. The SEO did work, though, and organic traffic started coming in.
Your first session is free, and after that it's one payment for a month. Two people have already paid.