01 — Project Overview

What is LexiChain?

LexiChain is a full-stack BFSI (Banking, Financial Services & Insurance) contract intelligence platform. It transforms raw PDF and image contract documents into structured, searchable, and verifiable data through a multi-layer pipeline:

Upload — Users upload insurance policies, loan agreements, or investment contracts.
AI Extraction — Google Gemini (primary) or Mistral AI (fallback) reads the document and extracts structured metadata.
RAG Q&A — Users can ask natural-language questions about any analyzed contract.
Blockchain Proof — Every document's SHA-256 hash is registered on Ethereum (Sepolia testnet or local Hardhat) providing tamper-proof, timestamped proof-of-deposit.
Notifications — The platform emails users about upcoming contract renewals and expiries.
Analytics — A dashboard aggregates contract statistics, type distributions, and status trends.

Feature List

Feature	Description
Authentication	Clerk-powered sign-in/sign-up with SSO support
Contract Upload	Drag-and-drop PDF/image upload via UploadThing
AI Analysis	Structured extraction: type, dates, premium, provider, key clauses
AI Fallback	Mistral Large + Pixtral vision model when Gemini is unavailable
Contract Q&A	RAG-grounded question answering on analyzed contracts
Blockchain Proof	On-chain document hash registration (Sepolia testnet)
Blockchain Explorer	In-app UI to verify document hashes and view transaction proofs
Email Notifications	SMTP-based renewal and expiry alerts
In-App Notifications	Real-time notification bar with read/dismiss
Analytics Dashboard	KPIs, status distribution, contract type charts (Recharts)
Dark / Light Mode	Full theme support via next-themes
PDF Certificate Export	Downloadable PDF certificates with QR codes
CSV Export	Contract list export to CSV

Technology Stack

Core Framework

Layer	Technology
Framework	Next.js 16.x (App Router)
Language	TypeScript 5.x (strict mode)
Runtime	Node.js ≥ 20
React	19.x

Frontend

Technology	Purpose
Tailwind CSS + tailwindcss-animate	Utility-first styling
shadcn/ui (Radix UI primitives)	Accessible component library
Lucide React	Icon set
Motion (Framer Motion v12)	Animations and micro-interactions
Recharts	Analytics charts
Sonner	Toast notifications
next-themes	Dark/light mode
react-hook-form + zod	Form validation

Backend & Data

Technology	Purpose
PostgreSQL	Primary relational database
Prisma ORM	Schema management, type-safe queries, migrations
Clerk	Authentication, user management
UploadThing	File upload and CDN storage
Nodemailer	SMTP email delivery

AI & Intelligence

Technology	Purpose
Google Gemini (via `@google/generative-ai`)	Primary multimodal contract extraction
Mistral AI (REST API)	Fallback extraction + OCR
Pixtral (Mistral Vision)	Image/scanned document fallback
Gemini text-embedding-004	Vector embeddings for RAG

Blockchain

Technology	Purpose
Solidity 0.8.24	Smart contract language
Hardhat	Compilation, testing, local node, deployment
ethers.js v6	Server-side blockchain interaction
Ethereum Sepolia	Production testnet (free, no cost)

PDF & Certificates

Technology	Purpose
PDFKit	Server-side PDF certificate generation
jsPDF + jspdf-autotable	Client-side PDF/table export
pdf-parse	PDF text extraction for OCR fallback
qrcode	QR code generation for certificates

Architecture Overview

┌─────────────────────────────────────────────────────────────────┐
│                        USER BROWSER                             │
│                   Next.js App Router UI                         │
└───────────────────────┬─────────────────────────────────────────┘
                        │
          ┌─────────────▼──────────────┐
          │    Clerk Middleware         │  Route protection (proxy.ts)
          │    (proxy.ts)               │  Blocks unauthenticated access
          └─────────────┬──────────────┘
                        │
          ┌─────────────▼──────────────┐
          │    Server Actions           │  lib/actions/* — authenticated
          │    & Route Handlers         │  server-side operations
          └──────┬──────────┬──────────┘
                 │          │
    ┌────────────▼──┐  ┌────▼───────────┐
    │  lib/services  │  │  app/api/*      │
    │  (domain logic)│  │  (webhooks,     │
    │                │  │   uploadthing)  │
    └────────────────┘  └────────────────┘
           │
    ┌──────┴──────────────────────────────────┐
    │          External Integrations           │
    │                                          │
    │  PostgreSQL   UploadThing   Gemini API   │
    │  (Prisma)     (file CDN)    (primary AI) │
    │                                          │
    │  Mistral AI   Ethereum      SMTP Server  │
    │  (fallback)   Sepolia       (email)      │
    └──────────────────────────────────────────┘

User Flows

User visits /sign-up
  → Clerk handles registration
  → Clerk fires webhook (user.created)
  → app/api/webhooks/clerk syncs User record to PostgreSQL
  → User redirected to /dashboard

2. Contract Upload & Analysis

User uploads PDF from /contracts
  → UploadThing receives file → stores on CDN → returns URL
  → saveContract() server action creates Contract row (status: UPLOADED)
  → User clicks "Analyze"
  → analyzeContractAction() sets status: PROCESSING
  → AIService downloads file → sends to Gemini → parses JSON response
  → ContractService.updateWithAIResults() saves extracted data
  → BlockchainService hashes file → registers hash on Sepolia
  → Status set to COMPLETED
  → NotificationService creates in-app + email notification

3. Contract Q&A (RAG)

User asks question in contract detail page
  → askContractQuestionAction() fetches contract + RAG chunks
  → RAGService finds most similar chunks via cosine similarity
  → AIService sends contract context + question to Gemini
  → Answer streamed back to UI

4. Blockchain Verification

User opens /blockchain explorer
  → BlockchainService.getNetworkStats() queries Sepolia node
  → User pastes document hash or views registered documents
  → BlockchainService.verifyOnChain() calls verifyDocument() on Solidity contract
  → Result shown: exists / timestamp / depositor address

Project Directory Structure

bfsi-project/
├── app/                    Next.js App Router
│   ├── (auth)/             Sign-in / Sign-up pages
│   ├── (dashboard)/        Protected workspace pages
│   │   ├── dashboard/      Analytics overview
│   │   ├── contacts/       Contract list & detail
│   │   └── blockchain/     Blockchain explorer
│   └── api/                Route handlers
│       ├── contracts/      Contract CRUD endpoints
│       ├── uploadthing/    UploadThing integration
│       └── webhooks/       Clerk webhook receiver
├── blockchain/             Hardhat smart contract project
│   ├── contracts/          Solidity source files
│   └── scripts/            Deployment scripts
├── components/             Reusable React components
│   ├── layout/             Shell, sidebar, header
│   └── ui/                 shadcn/ui design system
├── docs/                   This documentation folder
├── features/               Feature-scoped components
│   ├── ai/                 AI analysis UI
│   ├── analytics/          Dashboard charts
│   ├── auth/               Auth-related UI
│   ├── blockchain/         Blockchain explorer UI
│   ├── claims/             Claims management
│   ├── contracts/          Contract upload/list/detail
│   ├── home/               Landing page
│   └── notifications/      Notification center
├── hooks/                  Custom React hooks
├── lib/
│   ├── db/                 Prisma client singleton
│   ├── services/           All domain services (AI, Blockchain, etc.)
│   │   └── ai/             AI sub-modules (parser, normalizer, prompts)
│   ├── upload.ts           UploadThing configuration
│   └── utils.ts            Shared utility functions
├── prisma/                 Database schema and migrations
├── public/                 Static assets
├── scripts/                Dev tooling scripts
├── types/                  Shared TypeScript types
├── proxy.ts                Clerk middleware (route protection)
└── next.config.ts          Next.js configuration

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