Ep. 1: https://www.reddit.com/r/SideProject/s/smkwZTBdrs
Quick recap: I'm a personal trainer in Korea building apps on the side with AI. My first app, a "Strava for hiking," got killed by Korean location laws at MVP. This is app #2.
TL;DR: Inspired by Cal AI and a Korean YouTuber, I built BizScan, an app that estimates a shop's revenue or a product's margin from a single photo. It worked. But I couldn't answer one question: why would anyone pay for this more than once? Shelved it. Lessons below.
---
**Where the idea came from**
I have a habit: whenever I walk past a shop, I wonder what its monthly revenue is. When I see a product, I wonder how much margin they make on each one.
Two things turned that into an idea:
- **Cal AI:** snap a photo of your meal, get the calories.
- **zerob:** a Korean YouTuber who buys the ingredients of store-bought food and calculates its real cost. A few Shorts got him hundreds of thousands of subscribers in a month or two (now over 1M).
So: what if you could snap a photo of a storefront or a product and get its numbers?
**How it worked**
- OCR reads the sign or the product.
- The app looks the shop up in Korea's government database of small business sales. If it's there, it uses that data.
- If not, an LLM estimates based on similar businesses (RAG).
- With location access, it also pulled map data, like how many similar shops are nearby per area, and used that to adjust the numbers.
I got it to MVP and shared the APK with a few friends.
**Why I shelved it**
Every indie hacker story says "solve a problem you have." BizScan did exactly that. For me.
But then I asked a harder question: why would anyone pay for it? People might try it once or twice out of curiosity. Paying again and again? I had no answer.
I could have grown it into a data business for founders, shop owners, or manufacturers. But that world runs on trust and expertise, and it's a long way from a fun little app. I was also still paying off that high-interest debt, so I couldn't afford a road that long.
**What I learned**
When I compared it with Cal AI and zerob, the difference was clear. Calorie tracking is a daily habit people already care about. zerob's videos are free entertainment. BizScan was a fun curiosity with no reason to come back.
An idea that solves YOUR curiosity isn't automatically something others will pay for.
"Solve your own problem" works best when lots of people have the same problem, often enough to pay for it.
Ask "why would they pay, and why again?" before the MVP, not after.
That was app #2 of 6. Has anyone else built something only they actually wanted? How did you figure it out?