15, no dev background, and I just realized 'check if it sold' is way harder than it sounds

I'm 15, and for the past several months I've been building a tool that helps resellers cross-list products across Shopify, Etsy, and eBay.

It started because I kept reading through resale communities and noticing the same complaint over and over: an item sells on one platform, and it's still sitting live on two others because nobody has time to go delist it manually. Sometimes it sells twice before anyone catches it.

I'm not a professional developer. I've been learning as I go, mostly by building this thing and breaking it repeatedly. A lot of what I thought would be simple (like "just check if it sold") turned out to depend on details I didn't expect — different platforms expose different data, some don't let you check in real time at all, and I had to rework my approach more than once.

I don't have users yet. I've been posting in a few places to see if the problem I'm solving is one other people actually have, or if I've just been staring at it too long to see it clearly.

If you're curious what it looks like, it's linked in my profile. Happy to answer questions about any part of the build — the technical decisions, the mistakes, or what it's like working on something like this at this age.