CryptoBridger — Crypto Fiat Card MVP

A revolutionary crypto fiat card that lets you spend your crypto without selling it. Built on Solana with Anchor smart contracts, Lamyt enables credit mode spending, 2% cashback rewards, and daily interest on collateral.

🚀 Features

Core Functionality

• Credit & Debit Mode: Switch between direct crypto spending or using crypto as collateral for a credit line
• 2% Cashback Rewards: Earn up to 2% cashback in crypto on every purchase in Credit Mode
• Daily Interest: Unspent collateral earns interest 24/7
• Non-Custodial Security: Your keys, your crypto — backed by Anchor smart contracts
• Global Acceptance: Accepted at 100M+ merchants worldwide with Apple Pay & Google Pay support
• Instant Swaps: Best-rate token swaps powered by Jupiter DEX aggregator

Technical Highlights

• Solana Integration: High-speed, low-cost transactions
• Real-time Liquidation Protection: Automated risk management
• Multi-token Support: Deposit SOL and other supported tokens as collateral
• POS Simulator: Test card transactions in a simulated environment

🛠 Tech Stack

Frontend

• Next.js 16 - React framework with App Router
• TypeScript - Type-safe development
• Tailwind CSS - Utility-first styling
• Radix UI - Accessible component primitives
• Lucide React - Icon library

Backend

• Rust - High-performance systems programming
• Actix Web (assumed) - Web framework for API services

Blockchain

• Solana - High-performance blockchain
• Anchor Framework - Solana smart contract development
• Jupiter - DEX aggregator for token swaps

Infrastructure

• Docker - Containerization
• Kubernetes - Orchestration
• Terraform - Infrastructure as Code

📋 Prerequisites

• Node.js 18+
• Rust 1.70+
• Solana CLI tools
• Anchor CLI
• Docker & Docker Compose

🚀 Getting Started

1. Clone the Repository

git clone https://github.com/sks006/cryptoBridger.git
cd cryptoBridger

2. Setup Web Application

cd apps/web
npm install
npm run dev

The web app will be available at http://localhost:3000

3. Setup Backend

cd backend
cargo build
cargo run

4. Setup Solana Program

cd programs/lending_vault
anchor build
anchor deploy

5. Environment Configuration

Create .env.local in apps/web with:

NEXT_PUBLIC_SOLANA_RPC_URL=https://api.mainnet-beta.solana.com
NEXT_PUBLIC_JUPITER_API_URL=https://quote-api.jup.ag/v4

📖 Usage

For Users

1. Connect your Solana wallet
2. Deposit collateral (SOL or supported tokens)
3. Activate your virtual crypto to a flat Card
4. Start spending and earning rewards

For Developers

• Development: npm run dev in web app
• Building: npm run build
• Testing: Run tests in respective directories
• POS Simulation: Visit /pos-simulator to test card transactions

🏗 Architecture

crypto-fiat-card-mvp/

├── apps/
│   ├── web/                          # Your existing Next.js frontend (kept mostly unchanged)
│   │   ├── src/
│   │   │   ├── app/
│   │   │   │   ├── lamyt.tsx
│   │   │   │   ├── page.tsx                  # landing + connect wallet
│   │   │   │   ├── dashboard/
│   │   │   │   │   ├── page.tsx
│   │   │   │   │   └── transactions.tsx
│   │   │   │   ├── card/
│   │   │   │   │   ├── page.tsx
│   │   │   │   │   └── topup.tsx
│   │   │   │   ├── swap/
│   │   │   │   │   └── simulate.tsx
│   │   │   │   ├── pos-simulator/
│   │   │   │   │   └── page.tsx
│   │   │   │   └── nfc/                      # NEW for web
│   │   │   │       └── tap/page.tsx          # Web NFC demo page
│   │   │   ├── components/
│   │   │   │   ├── WalletConnect.tsx
│   │   │   │   ├── HealthFactorMeter.tsx
│   │   │   │   ├── CardBalance.tsx
│   │   │   │   ├── NFCRingAnimation.tsx
│   │   │   │   └── NFCTapButton.tsx          # NEW: Simulate / Real Web NFC button
│   │   │   ├── lib/
│   │   │   │   ├── solana.ts
│   │   │   │   ├── jupiter.ts
│   │   │   │   ├── anchor-client.ts
│   │   │   │   ├── api-client.ts
│   │   │   │   └── nfc/
│   │   │   │       ├── web-nfc.ts            # Web NFC API
│   │   │   │       └── mock-nfc.ts           # Fallback simulation
│   │   │   └── hooks/
│   │   │       ├── useHealthFactor.ts
│   │   │       ├── useCardBalance.ts
│   │   │       └── useNFCTap.ts              # Unified hook (Web + Mock)
│   │   ├── public/
│   │   ├── next.config.js
│   │   ├── tailwind.config.ts
│   │   └── package.json
│   │
│   └── mobile/                              # ✦ NEW — simplified RN app
│       ├── src/
│       │   ├── app/
│       │   │   ├── index.tsx               # wallet connect entry
│       │   │   ├── dashboard/
│       │   │   │   └── screen.tsx
│       │   │   ├── card/
│       │   │   │   └── screen.tsx
│       │   │   └── nfc/
│       │   │       ├── TapScreen.tsx       # ✦ NFC tap UI (mock)
│       │   │       └── MockProvision.tsx   # ✦ simulated card-to-wallet flow
│       │   ├── components/
│       │   │   ├── WalletConnect.tsx
│       │   │   ├── CardBalance.tsx
│       │   │   └── NFCRingAnimation.tsx    # ✦ simple tap pulse
│       │   └── lib/
│       │       ├── solana.ts
│       │       ├── jupiter.ts
│       │       ├── anchor-client.ts
│       │       ├── api-client.ts
│       │       └── nfc/
│       │           ├── nfc-manager.ts      # ✦ react-native-nfc-manager wrapper
│       │           └── mock-hce.ts         # ✦ Android HCE stub (logs APDU)
│       ├── android/
│       │   └── app/src/main/
│       │       ├── AndroidManifest.xml     # ✦ NFC + HCE permissions
│       │       └── java/.../
│       │           └── HCEService.java     # ✦ stub HostApduService
│       ├── ios/
│       │   └── CryptoCardMVP/
│       │       └── Info.plist              # ✦ NFCReaderUsageDescription
│       ├── package.json
│       ├── metro.config.js
│       └── app.json
│
├── programs/
|   ├── lending-vault/                      Your existing fixed lending protocol —
|   │   ├── src/
|   │   │   ├── lib.rs
|   │   │   ├── instructions/
|   │   │   │   ├── deposit.rs
|   │   │   │   ├── withdraw.rs
|   │   │   │   ├── borrow.rs                  # reads Pyth price feed
|   │   │   │   ├── repay.rs
|   │   │   │   └── liquidate.rs               # reads Pyth price feed
|   │   │   ├── state/
|   │   │   │   ├── vault.rs                   # includes price_feed Pubkey
|   │   │   │   └── user_position.rs
|   │   │   └── error.rs
|   │   ├── Anchor.toml
|   │   └── Cargo.toml                         # + pyth-sdk-solana
│
├── backend/
│   ├── src/
│   │   ├── main.rs
│   │   ├── handlers/
│   │   │   ├── health.rs
│   │   │   ├── auth.rs
│   │   │   ├── card.rs
│   │   │   ├── swipe.rs
│   │   │   └── nfc.rs                      # ✦ NEW
│   │   │       # POST /nfc/tap  → mock JIT, returns receipt JSON
│   │   │       # POST /nfc/provision → returns mock token { pan_token, exp }
│   │   ├── solana/
│   │   │   ├── client.rs
│   │   │   ├── vault_ix.rs
│   │   │   └── jupiter_quote.rs
│   │   ├── state/
│   │   │   ├── memory_store.rs             # HashMap<UserId, Session>
│   │   │   └── nfc_store.rs                # ✦ HashMap<DeviceId, MockToken>
│   │   └── utils/
│   │       ├── ltv.rs
│   │       └── nfc_nonce.rs                # ✦ one-time nonce gen (in-memory)
│   ├── Cargo.toml
│   └── .env
│
├── docs/
│   └── whitepaper/
│       ├── MiCA_summary.md
│       └── nfc_flow_notes.md               # ✦ APDU tap → mock JIT diagram
│
├── scripts/
│   ├── deploy-program.sh
│   ├── seed-mock-users.sh
│   └── simulate-nfc-tap.sh                 # ✦ curl POST /nfc/tap shortcut
│
├── tests/
│   └── e2e/
│       ├── swipe.test.ts
│       └── nfc_tap.test.ts                 # ✦ Detox NFC mock tap test
│
├── HACKATHON_README.md
└── .gitignore

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests
5. Submit a pull request

⚠️ Disclaimer

This is an MVP (Minimum Viable Product) and is for demonstration purposes. Not intended for production use without further development and security audits.

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Built with ❤️ on Solana