ReLoop

Problem Statement

The unchecked use of single-use plastic bags remains a critical environmental challenge, leading to overflowing landfills, marine pollution, and increased greenhouse gas emissions. As highlighted by Walmart Canada's 2024 sustainability challenge (source), most recycling initiatives lack transparency, traceability, and effective incentives for both consumers and stakeholders. There is a pressing need for a tech-driven, transparent, and engaging solution that not only eliminates single-use plastics but also motivates users and partners to participate in a circular economy.

ReLoop addresses this challenge by providing a robust backend system for a reusable bag return ecosystem. The platform leverages unique QR-coded bags, digital transaction tracking, and an incentive-based model to encourage sustainable behavior. By enabling real-time lifecycle monitoring, role-based access for users and workers, and seamless partner/vendor integration, ReLoop ensures that every bag's journey—from issuance to reuse or recycling—is transparent, auditable, and rewarding. This approach empowers retailers, staff, and customers to collaboratively reduce plastic waste and build a scalable, sustainable future.

About the Project

ReLoop is a backend system designed to power a reusable bag return ecosystem, inspired by Walmart Canada’s 2024 initiative and enhanced with modern technology and incentives. The system eliminates single-use plastic bags by providing customers with uniquely identifiable, QR-coded reusable bags at checkout. Each bag’s journey—from issuance to return or recycling—is tracked in detail.

How It Works:

• Receive Bag: Customers receive a reusable bag with a unique QR code at the point of sale.
• Return Bag: Bags can be returned during the next visit or at any partner/vendor location.
• Earn Incentives: Users earn credits based on the bag’s condition and whether it is reused or recycled. Reuse yields higher rewards; recycling still provides value.
• Lifecycle Tracking: Every bag’s usage count, transaction history, and approval logs (including which worker processed the bag) are recorded.
• Worker & Partner Integration: Store staff and partner vendors can scan, approve, and process bags, with all actions logged for transparency.

Key Features:

• Smart Bag Tracker: Monitors each bag’s lifecycle, ownership, and usage.
• Credit Engine: Dynamically calculates rewards based on action and bag condition.
• Role-Based Access: Separate dashboards and permissions for users and workers.
• Admin & Vendor Tools: Enables third-party participation and digital approval/rejection of bag status.
• Secure & Scalable: Built with FastAPI, JWT authentication, and PostgreSQL for robust, secure operations.

Making ReLoop Popular in India: The ReLoop reward system is designed to penetrate the Indian market by offering instant, tangible incentives such as store credits, loyalty points, or discounts—rewards that resonate strongly with Indian consumers. By integrating with popular retail chains and local vendors, and supporting digital payment and wallet systems widely used in India, ReLoop encourages mass adoption. The gamified credit system, transparent tracking, and ease of use make sustainable behavior both rewarding and aspirational, helping to drive real change and make ReLoop a household name among Indian users.

By combining sustainability, technology, and incentives, ReLoop aims to drive real behavior change and make circular economy models practical for retailers and customers alike.

System Architecture

Below are the key architecture diagrams illustrating the ReLoop platform:

1. High-Level Overview Of User Dashboard

2. High-Level Overview Of Worker Dashboard

3. Bag Lifecycle & Tracking Flow

_Diagrams created with Excalidraw.

Demo Video

Watch a quick demo of ReLoop in action:

API Endpoints

Authentication

• POST /auth/user/signup - User registration
• POST /auth/user/login - User login
• POST /auth/worker/signup - Worker registration
• POST /auth/worker/login - Worker login

User Dashboard

• GET /dashboard/user/purchase_transactions
• GET /dashboard/user/coin_transactions
• GET /dashboard/user/total_coin
• GET /dashboard/user/profile
• POST /dashboard/user/redeem/{coin_amount}

Worker Dashboard

• GET /dashboard/worker/scan_transactions
• GET /dashboard/worker/profile
• POST /dashboard/worker/scan_qr
• POST /dashboard/worker/about_bag

Project Structure

ReLoop/
│
├── Auth/
│   └── auth.py
├── Dashboard/
│   ├── dashboard.py
│   ├── user_dashboard.py
│   └── worker_dashboard.py
├── Database/
│   ├── Engine/
│   │   └── __init__.py
│   └── ORM_Models/
│       ├── auth_models.py
│       ├── bag_models.py
│       ├── info_models.py
│       ├── response_models.py
│       ├── token_models.py
│       └── transaction_models.py
├── Utils/
│   ├── dependency.py
│   ├── enums.py
│   ├── exceptions.py
│   ├── router_classes.py
│   └── utility_functions.py
├── config.py
├── main.py
├── pyproject.toml
└── README.md

Setup

1. Clone the repository

   git clone <your-repo-url>
   cd ReLoop

2. Create and activate a virtual environment

   python -m venv .venv
   .venv\Scripts\activate

3. Install dependencies with uv

   uv sync

4. Set up environment variables
   Create a .env file in the root directory with:

   DATABASE_URL=postgresql://user:password@localhost/dbname
   SECRET_KEY=your_secret_key
   ALGORITHM=HS256
   

5. Run the application

   uvicorn main:app --reload

Dependencies

See pyproject.toml for the full list, including:

• FastAPI
• SQLModel
• PostgreSQL (via psycopg2)
• bcrypt, passlib
• pyjwt
• python-dotenv
• opencv-python, pyzbar
• numpy