Stop Overpaying

Inspiration

As a homeowner frustrated by opaque property tax assessments, I noticed many peers in my community overpaid due to lack of tools to verify fairness. I wanted to build something accessible to cut through bureaucracy and empower homeowners to challenge overassessments.

What it does

PropertyTax Analyzer lets homeowners input property details to get a Fairness Score (0-100) comparing their tax assessment to local comparable properties. It estimates savings, provides region-specific appeal guidance, and generates professional appeal letters (PDF/Word) to reduce tax burdens.

How we built it

I started by mapping core user workflows (input → analysis → appeal → payment). I integrated tax database APIs to source comparable property data, built an AI model to calculate Fairness Scores using 8 valuation factors, and integrated Stripe/PayPal for secure payments. The frontend was built with React for responsiveness, and I ensured compliance with GDPR/CCPA and WCAG 2.1.

Challenges we ran into

Sourcing reliable, region-specific tax data APIs (especially across EU/US/Australia) was tough—some regions had limited public data. Ensuring session data persisted for 24 hours without logins while complying with privacy laws also required creative storage solutions. Handling edge cases (e.g., insufficient comparable properties) demanded robust error handling.

Accomplishments that we're proud of

We built a tool that’s accessible (WCAG 2.1 compliant) and works across desktop/mobile. The AI Fairness Score is accurate, and users can generate ready-to-submit appeal letters in minutes. We also implemented a transparent commission model (25% of verified savings) that aligns our success with homeowners.

What we learned

I deepened my understanding of cross-regional privacy compliance (GDPR/CCPA) and tax regulation nuances across North America, Europe, and Australia. I also learned to balance accuracy with usability—simplifying complex tax data into actionable insights for non-technical users.

What's next for this project

We plan to add multi-language support, integrate with tax authority systems for auto-appeal submission, and build a mobile app. We’ll also expand to more regions and add automated annual tax assessment monitoring to alert users of new overassessment risks.

Built With

• paypal
• postgresql
• stripe
• taxdatabaseapi