Underpriced App went live on Google Play - Profit Checker for Resellers

Hey IH! 👋

After months of building, I finally shipped the Android version of Underpriced and wanted to share the journey.

The problem:
I've been into reselling/flipping as a side hustle. The hardest part isn't finding items - it's quickly evaluating whether something is worth buying. You're standing in a thrift store, holding some vintage gadget, and you need to decide in 30 seconds if it's worth $5 or $500.

The solution:
Underpriced uses AI (Gemini) to analyze product photos and cross-references real sold data from eBay, Mercari, etc. to give instant pricing estimates and flip recommendations.

Tech stack:

• React + Vite frontend
• Vercel serverless functions for API
• Firebase for auth/data
• Capacitor for the Android wrapper
• Gemini API for image analysis
• eBay API for comp data

What I learned:

1. Capacitor made the web → Android transition surprisingly smooth
2. AI costs add up fast - had to implement smart caching and credit systems
3. The reselling community is incredibly engaged and gives great feedback

Current state:

• Web app has been live since November 2025
• Android just launched this week
• Building toward profitability with a credit-based model

I'd genuinely love feedback from this community:

• How's the value prop sound?
• Any suggestions on the pricing/credit model for AI-based tools?
• What would make you actually use something like this?

Play Store: https://play.google.com/store/apps/details?id=com.underpriced.app

Web: https://underpriced.app

Thanks for reading! Happy to answer any questions about the build.