A revolutionary “cardless” payment method that allows users to make purchases using only their voice.
Built at ShellHacks 2025 in just 36 hours!
VPay enables customers to walk into any store and complete transactions by simply speaking to a payment terminal.
No phone, no card, just your voice.
This innovative approach not only helps people who’ve forgotten their wallet or phone but also makes payments more accessible for individuals with disabilities.
The idea for VPay came from a conversation with one of our teammate’s parents about how inconvenient it can be to forget your payment methods.
While researching, we found that a university in China had implemented a facial payment system, which inspired us to take the concept even further by using voice authentication instead.
- 🎤 Voice-Only Payments – Complete transactions using natural voice commands
- 🔐 Secure Authentication – Custom voice embedding system for user verification (Not fully implemented)
- 🧏 Accessibility-Focused – Designed to make payments more inclusive
- ⚡ Real-Time Processing – Fast audio capture and backend processing
- 💳 Payment Simulation – Integrated Stripe API to emulate real transactions
- Python
- FastAPI – Web framework for backend routes
- Uvicorn – ASGI server to run FastAPI
- Google ADK (Agent Development Kit) – For agent orchestration
- Gemini 2.5 Flash – Large Language Model (LLM) used for natural language understanding
- Speech Recognition – Converts audio to text
- SQLite3 – Stores custom voice embeddings for authentication
- Stripe API – Handles simulated payments
- React – User interface framework
- Tailwind CSS – Styling
- JavaScript – Interactivity and logic
- MediaRecorder – Captures voice input
- getUserMedia – Accesses the user’s microphone
- User speaks a command like “Pay 20 dollars to Target.”
- Frontend captures the voice using MediaRecorder + getUserMedia.
- Audio is sent to the backend (FastAPI) via RESTful API.
- Speech Recognition converts it to text.
- Google ADK and Gemini 2.5 Flash parse the intent (amount, payee).
- The backend triggers Stripe API to simulate payment.
- Result is returned to the frontend and displayed in real-time.
- Python 3.8+
- Node.js and npm
- Stripe API key
- Google Cloud account with ADK access
# Clone the repository
git clone https://github.com/KhangHo10/Vpay.git
cd Vpay
# Create and activate a virtual environment
python -m venv venv
source venv/bin/activate # On Windows: venv\Scripts\activate
# Create a .env file in the root directory
STRIPE_API_KEY=your_stripe_key
GOOGLE_ADK_KEY=your_google_adk_key
# Install backend dependencies
pip install -r requirements.txt
# Install frontend dependencies
cd frontend
npm install
# Run the backend
uvicorn main:app --reload
# Run the frontend
npm start- Khang Ho
- Zara Maraj
- Haruki Horiuchi
- Miguel Ávila
Built in 36+ hours at ShellHacks 2025 — Florida’s largest hackathon!
We learned, built, and collaborated through sleepless nights (and probably too much caffeine).