ALERG'Z

Automated allergen risk analysis with actionable alternatives.

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A RowdyHacks XI Creation

🚀 Setup & Installation

Prerequisites

Backend Setup (Run from backend/ directory)

cd backend
python -m venv venv
source venv/bin/activate  # Windows: venv\Scripts\activate
pip install -r requirements.txt
cp .env.example .env
# Add your OpenRouter API key to .env: OPENROUTER_API_KEY=sk-or-v1-xxxxx
uvicorn main:app --reload --host 0.0.0.0 --port 8003

Frontend Setup (Run from frontend/allergen-app/ directory)

cd frontend/allergen-app
npm install
cp .env.example .env
# Add your machine's IP to .env: EXPO_PUBLIC_API_BASE_URL=http://YOUR_IP:8003
npx expo start

Find your IP:

  • macOS/Linux: ifconfig | grep "inet "
  • Windows: ipconfig

Testing:

  • Press i for iOS Simulator (macOS)
  • Press a for Android Emulator
  • Scan QR with Expo Go app (ensure same WiFi network)

Verify Backend: Visit http://localhost:8003/docs for API documentation

💡 Inspiration

Food allergies can turn a simple grocery trip into a stressful guessing game. Our team wanted to make that process easier, safer, and faster — especially for people who constantly need to double-check ingredients or risk severe reactions.

We created an app allowing you to scan any product, instantly know if it’s safe, and get smart alternatives powered by the gold-standard of food databases, supplemented by OpenAI. That’s ALERG'Z — a personalized food companion built to bring peace of mind to those with allergies 👍

⚙️ What it does

ALERG'Z is a mobile app that helps users identify allergy-safe foods with just a barcode scan.

Here’s how it works:
| Step | Description| | ------------- |:-------------:| | 1. User Profile Setup |Users input their allergens when they first open the app, user data is stored with an SQLite database| | 2. Product Scanning |When a barcode is scanned, ALERG'Z instantly fetches data from OpenFoodFacts to identify the product and its ingredients.| | 3. Allergen Detection |The backend cross-checks ingredients against the user’s allergy profile.| | 4. AI-Driven Alternatives |If a product isn’t safe, ALERG'Z uses ChatGPT (via OpenRouter) to suggest similar, allergy-friendly alternatives tailored to the user’s region.| | 5. Visual Feedback |Each recommendation includes live-fetched product images for a smooth, engaging experience.|

All of this happens in seconds, giving users clear, visual answers and personalized options — no ingredient lists or guesswork required.

🛠️ How we built it

  • Frontend: A sleek, modern React Native interface designed for both speed and accessibility. We focused on a clean user experience where every tap feels instant and intuitive.
  • Backend: Built with FastAPI in Python, enabling rapid, concurrent API calls to OpenFoodFacts and ChatGPT's generative model for alternative recommendations.
  • APIs & Data:
    • OpenFoodFacts API for product details and UPC lookups
    • OpenAI API for intelligent food alternative generation
    • OpenFoodFacts images for visual product data
  • Architecture:
    • Asynchronous background threads to fetch product images dynamically
    • JSON-structured responses to sync data seamlessly with the React Native client
    • User authentication and profile management using SQLAlchemy + FastAPI ORM

This setup allowed us to achieve real-time scanning and recommendations — even on limited bandwidth.

🚧 Challenges we ran into

  • Image Updating: Allowing dynamic loading of page elements to ensure a fast, accessible user experience.
  • API Rate Limits: Balancing performance while staying within OpenFoodFacts and OpenAI rate constraints required optimization and caching logic.
  • Prompt Engineering: Tuning the AI prompt for consistent, list-formatted responses from OpenRouter took a lot of iteration.
  • Cross-Platform Sync: Ensuring React Native and FastAPI communicated perfectly across threads and sockets pushed us to fine-tune CORS and websocket behavior.

🏆 Accomplishments that we’re proud of

  • Built a fully functional allergy-detection and recommendation system from scratch in just a 24 hours.
  • Achieved real-time barcode scanning and analysis with a fast, responsive UI.
  • Successfully integrated multiple APIs and AI models into one seamless experience.
  • Designed a clean, user-first mobile interface that feels both modern and trustworthy.

Most importantly, we created something that could genuinely make life easier for people managing allergies every day.

📚 What we learned

  • How to efficiently orchestrate multi-API workflows in FastAPI using background tasks and concurrent threading.
  • The power of prompt design — small phrasing changes can dramatically impact AI output.
  • Strategies for frontend-backend synchronization in real-time, user-centric applications.
  • How valuable user empathy is when building healthcare-adjacent products — the human side matters just as much as the technical side.

🚀 What’s next for ALERG'Z

  • Ingredient-level risk scoring to show how “safe” a product is for a specific allergy.
  • Expanded database support for region-specific food APIs (USDA, Tesco, Carrefour).
  • Camera-based label scanning for offline use when barcodes aren’t available.
  • Personalized dashboards to track safe foods, allergen exposure, and nutrition trends.
  • Social recommendations, allowing users to share safe product discoveries.

Our vision is to make ALERG'Z the go-to app for allergy-conscious consumers — empowering users to eat confidently, anywhere.

📁 Repo Structure

ALERGZ
├── README.md
├── LICENSE
├── .gitignore
├── backend
│   ├── main.py
│   ├── requirements.txt
│   ├── allergen.db
│   └── app
│       ├── api
│       │   ├── scan.py
│       │   ├── recommend.py
│       │   └── __init__.py
│       ├── database
│       │   ├── models.py
│       │   ├── db.py
│       │   └── __init__.py
│       ├── schemas
│       │   └── product.py
│       └── __init__.py
├── frontend
│   └── allergen-app
│       ├── package.json
│       ├── tsconfig.json
│       ├── babel.config.js
│       ├── eslint.config.js
│       ├── .env
│       ├── app
│       │   ├── _layout.tsx
│       │   ├── (tabs)
│       │   │   ├── screen1.tsx
│       │   │   ├── screen2.tsx
│       │   │   ├── screen3_camera.tsx
│       │   │   └── explore.tsx
│       │   └── components
│       │       ├── GlassSearchBar.tsx
│       │       ├── SelectedItemsArea.tsx
│       │       └── ui
│       │           └── icon-symbol.tsx
│       ├── assets
│       │   └── (images, icons)
│       └── scripts
│           └── reset-project.js
├── docs
│   └── (design / hackathon notes)
└── misc

Built With

  • ai
  • babel
  • expo.io
  • expo/vector-icons
  • fastapi
  • gorhom/bottom-sheet-backend:-fastapi-(python)-with-openai/openrouter-client-integration-database:-sqlite-using-sqlalchemy-external-apis:-openfoodfacts-(product-lookup)
  • node/npm
  • openai-(recommendations)
  • openfoodfacts-api
  • openrouter
  • postgresql
  • python
  • python-mobile-frontend:-expo-(react-native)-+-expo-router
  • react-native
  • react-native-reanimated
  • sqlite
  • typescript
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