All Receipts (Light Mode)
Upload Receipt (Light Mode)
Dashboard (Dark Mode)
Landing Page (Dark Mode)
Folders (Light Mode)

🧾 PaperTrail

Overview

PaperTrail is a secure fintech platform that uses AI, OCR, and Gmail integration to automatically collect, parse, and organize receipts into a personal or business expense dashboard. It streamlines expense tracking by combining automation, analytics, and intuitive design—all in one place.

💡 Inspiration

Our team was inspired by a simple frustration: receipts are always getting lost. Whether it’s a crumpled paper receipt or a digital one buried in an inbox, managing them manually is time-consuming and messy. We wanted to solve that by creating a smart, automated system that could collect and organize receipts seamlessly—helping both individuals and small businesses keep track of their spending effortlessly.

🧠 What We Learned

This project pushed us to explore new technologies and problem-solving strategies. We learned how to:

Integrate multiple APIs (Gmail, Gemini, Auth0, Supabase) cohesively.

Use Gemini 2.5 Flash for OCR and structured data extraction.

Work with authentication flows using Supabase and Auth0.

Visualize data effectively with pie, bar, line, and dot charts.

Our AI pipeline can be summarized as:

𝑓_receipt

𝑃 ( 𝐺 ( 𝐼 ) ) f receipt

=P(G(I))

where 𝐼 I is the image or PDF input, 𝐺 G is the Gemini model for extraction, and 𝑃 P parses the structured output into fields like merchant, date, and total.

⚙️ How We Built It

Frontend: Next.js + Tailwind CSS (with dark mode)

Backend: Supabase for database and authentication

AI: Gemini 2.5 Flash for OCR and structured text extraction

Email Integration: Gmail API for automatically fetching and parsing digital receipts

Auth: Auth0 for secure login and user management

Core features:

Dashboard with visual analytics

Upload page (including live camera capture for receipts)

All receipts view and folder organization

Automatic Gmail receipt syncing

🚧 Challenges

We faced several hurdles:

Integrating Gmail API with OAuth was tricky and time-consuming.

Figuring out the exact input/output structure for Gemini’s extraction model required a lot of testing.

OCR accuracy varied across different lighting and receipt types.

Maintaining consistent styling across pages (especially with dark mode) was challenging under tight time constraints.

🌍 Vision

We see PaperTrail helping individual users and small businesses simplify expense tracking. In the future, we’d love to add:

AI-powered expense categorization

Export options (e.g., CSV or QuickBooks)

Budgeting insights based on spending patterns

🏁 Takeaway

PaperTrail taught us how powerful AI can be when combined with thoughtful UX and strong engineering. It started with a simple annoyance—lost receipts—and became a project that could genuinely help people stay financially organized with minimal effort.