Inspiration
Families often share financial responsibilities across children, adults, and older relatives, but payment alerts usually arrive after money has moved. Guardian Pay explores how AI and PayPal’s authorization flow could give families a chance to review risky payments before they are captured.
What it does
Guardian Pay applies member-specific spending limits and evaluates recipient trust, payment history, and context. Routine payments can proceed with minimal friction, moderate payments notify the family head, and high-value or suspicious requests require review. An external-link safety check asks who requested the payment and why. The family head can then approve a held payment or block it.
How we built it
The app uses Next.js, TypeScript, and SQLite. Gemini returns a structured risk assessment, which Zod validates before it reaches a deterministic policy gate. The gate enforces spending limits and safety rules; AI can raise a payment’s risk tier, but cannot lower a tier required by those rules. PayPal Sandbox Orders and Payments APIs provide the authorization, capture, and void flow. The prototype also includes a family dashboard, notifications, transaction history, saved contacts, QR scanning, and five demo scenarios.
Challenges we ran into
A key challenge was making AI useful without letting it control payment decisions. We treated payment notes as untrusted input and kept spending rules in deterministic code. We also had to coordinate the payment lifecycle—authorization, capture, void, notifications, and expiry—so the app’s status reflects the PayPal action. For external links, we added safety questions whose risky answers force family review.
Accomplishments that we're proud of
The policy gate has 30 passing tests covering member limits, new recipients, AI escalation, uncertainty, and suspicious link answers. The production build and TypeScript checks pass. We’re proud that the prototype shows both a low-friction payment path and a human review path in one family-focused experience.
What we learned
AI is better suited to interpreting uncertain context than enforcing financial boundaries. Keeping risk assessment separate from deterministic policy makes the result easier to explain and keeps the family’s rules in control. Clear status messages and review reasons are also essential when a payment is held.
What's next for Guardian Pay
Before any public deployment, Guardian Pay needs sign-in and server-side family-role authorization. Next steps also include end-to-end PayPal Sandbox tests, persistent production storage, stronger privacy controls, and testing the experience with families. This project is a Sandbox prototype with simulated recipients—not a real-money product or a UPI integration.
Built With
- next.js
- paypal
- react
- sqlite
- tailwind
- typescript
