Home screen , Simple to use Scan and Create Option
View all the contracts/Agreements created
Details of each contract , with ability for mutual verification and tracking of progres
QR for seamless contract term review by other party

TrustBridge: A Platform for Trustworthy Informal Lending

Inspiration

As bachelor college students, we often faced the inefficiencies and awkwardness of informal lending within our friend groups. Challenges included tracking repayments, sending reminders, and the risk of straining friendships over financial matters. Similarly, we observed a more significant issue in rural communities, where farmers often rely on verbal agreements for loans. These agreements are prone to disputes due to forgotten or altered terms, leading to financial hardship.

This blend of personal experience and societal observation inspired us to create TrustBridge, a platform for securely digitizing and formalizing informal lending.

What We Learned

1. Mobile App Development with Flutter

We developed a cross-platform application using Flutter, exploring its widget-based architecture and state management through Riverpod.

2. Blockchain as a Ledger

We leveraged Polygon, a layer-2 Ethereum scaling solution, for its low gas fees and fast transactions. This ensured an immutable, transparent, and secure record of financial transactions.

3. API Integration

We designed and integrated REST APIs to connect the Flutter frontend with the backend services and blockchain.

4. UI/UX Design for Mobile

We focused on creating an intuitive interface tailored to simplify financial transactions for non-tech-savvy users, especially in rural areas.

5. Importance of User Research

By understanding the pain points of college students and rural borrowers, we built solutions aligned with their real-world needs.

6. KYC and Legal Implications

We studied regulatory requirements for KYC (Know Your Customer) compliance and data privacy to ensure the platform adhered to legal standards.

How We Built It

LendSafe was built using the following technologies:

Frontend

Framework: Flutter
State Management: Riverpod
Design System: Material Design

Backend

Framework: Node.js with Express.js
Authentication: JSON Web Tokens (JWT) for secure login and user sessions
API Design: REST APIs for seamless communication

Blockchain

Platform: Polygon (Ethereum Layer 2)
Smart Contracts: Written in Solidity to handle transactions and agreements. Deployed using Hardhat.
Wallet Integration: Metamask and WalletConnect for accessibility.

Database

Type: PostgreSQL
Purpose: For storing user profiles, off-chain data, and contract metadata.

Cloud Platform

Hosting: AWS EC2 and S3 for backend hosting and file storage.
CI/CD: GitHub Actions for continuous integration and deployment.

Notes-to-Contract Conversion

Tech Used: A rule-based engine using OpenAI APIs for natural language processing. This maps informal notes into structured contract fields.

KYC Verification

Tool: Integrated Signzy API for automated KYC, ensuring a smooth user onboarding experience.

Core Development Process

Designing the mobile UI and user flow with Flutter.
Developing backend APIs for user authentication, data management, and blockchain communication.
Implementing Polygon smart contracts for transaction and contract recording.
Building the "Notes-to-Contract" feature using NLP tools.
Integrating Signzy for seamless KYC verification.
Conducting extensive testing across devices and iterating based on feedback.

Challenges We Faced

1. Flutter Learning Curve

Mastering Flutter's advanced features, such as custom animations and Riverpod for state management, was time-intensive.

2. Backend-Blockchain Integration

Achieving real-time synchronization between blockchain transactions and off-chain data storage was complex but crucial for data consistency.

3. Balancing Security and Usability

Designing a secure financial app without overwhelming users with complexity required extensive prototyping and user testing.

4. Simplifying Complex Logic

Translating informal agreements into structured contracts that were both user-friendly and legally sound posed a significant challenge.

5. Notes-to-Contract Conversion

Accurately mapping informal notes to structured fields demanded robust rule-based NLP models and context understanding.

6. KYC Compliance

Ensuring a balance between user privacy and strict regulatory requirements required in-depth research and API implementation.

7. Data Synchronization

Ensuring consistent updates between the Polygon blockchain and PostgreSQL database was critical for maintaining trust in the system.

Conclusion

TrustBridge represents a blend of technology and empathy, aiming to address both personal and societal challenges in informal lending. Through the use of modern tools like Flutter, Polygon, and NLP, we have built a secure, user-friendly platform that bridges the gap between informal agreements and trustworthy digital solutions.