HackTX 2025

Inspiration

We all talk about going green, but when it comes to our money, we’re basically in the dark. Every swipe of our card has an environmental footprint, but no one knows how much their daily spending impacts the planet. As students who care about both technology and sustainability, we wanted to bridge that gap.

We realized that financial tools are great at tracking budgets, but not impact. We wanted to make a bank app that also displayed how much carbon was emitted by a user's spending. That question sparked EcoFin Carbon, a platform that connects personal finance with environmental awareness.

What it does

EcoFin Carbon calculates and visualizes the carbon footprint of your financial transactions. By linking a user’s bank or card data, the app breaks down emissions by category, like transportation, food, shopping, or entertainment, and translates them into understandable insights.

Key features include:

Transaction-based emission tracking, automatic carbon estimates for each purchase.
Dashboard visualization, dynamic charts showing spending vs. carbon footprint.
Personalized recommendations, actionable tips to reduce emissions based on spending habits.
Offset integration (future feature), connect users to verified carbon offset programs directly through the app.

In short, EcoFin Carbon helps people make greener financial choices without changing how they spend, how they see it.

How we built it

We built EcoFin Carbon using a mix of financial APIs, machine learning, and data visualization libraries:

Frontend: React + TailwindCSS for a clean, responsive UI.

Backend: Node.js + Express for API handling and user authentication.

Database: Nessie API (MongoDB in the future) for user storage and transaction data.

APIs & Data Sources:

Carbon Interface API for emission factor calculations.

Google Gemini API for LLM chatbot

Visualization: Recharts for interactive graphs and category insights.

Our model maps merchant categories (MCC codes) to estimated emission intensities using open-source carbon factor data. We implemented a simple calculation function:

Carbon Emission = Transaction Amount × Category Emission Factor

Challenges we ran into

Data Inconsistency: Emission factors for different products and services vary widely and aren’t standardized, especially with our authorization feature and user data.

Accuracy vs. Usability: Balancing scientific precision with a smooth user experience was tough, we wanted something reliable and user-friendly.

Time Constraints: Building a polished product with multiple API connections in under 24 hours required tight coordination.

Accomplishments that we're proud of

Built a fully functional prototype that tracks and visualizes real transaction-based carbon data.

Developed an intuitive dashboard that turns complex environmental data into simple visuals.

Created a scalable architecture for adding features like offsets, leaderboards, and sustainability goals.

Most importantly, we turned climate awareness into a tangible, personal experience through fintech.

What we learned

How to integrate financial APIs securely while handling sensitive data responsibly.

The importance of data standardization in sustainability tech, and that accurate carbon modeling depends heavily on consistent sources.

That user engagement matters as much as accuracy, visual design can make sustainability more approachable.

Collaboration and time management are everything in a hackathon, especially when merging backend logic with frontend design at 4 AM.

What's next for EcoFin Carbon

We want to take EcoFin Carbon beyond the hackathon by: Training a smarter model to provide personalized sustainability insights based on user behavior.

Launching a mobile version for on-the-go carbon tracking.

Collaborating with banks and fintech companies (like Capital One) to integrate this tool directly into existing finance apps.

Our long-term vision is to make eco-conscious spending the default, not the exception.