mrgnlend Interface (TypeScript)

A TypeScript application for interacting with mrgnlend (marginfi v2) protocol for lending SOL and managing lending positions.

Current Status

✅ Complete UI/UX Flow: Full interactive command-line interface
✅ Wallet Integration: SOL balance checking and price fetching
✅ Menu System: All requested flows (lend, withdraw, status)
✅ mrgnlend Integration: REAL TRANSACTIONS - Actual marginfi v2 program interactions ⚠️ Incomplete APY labels: APY information for banks is incorrect/ incomplete ⚠️ Suggested RPC: Helius free RPC is not compatible, but quicknode free plan is

Features

• 💰 Wallet Status: View your available tokens (value > $0.1) with USD values
• 🏦 mrgnlend Status: Check your current lending positions and earned interest
• 💸 Lending Flow: Lend SOL to earn lending interest with 0% platform fees
• 🔄 Withdrawal Flow: Withdraw SOL from lending positions (no fees)
• 📋 Interactive Menu: Easy-to-use command-line interface
• 🛡️ Insurance Protection: Your funds are protected by marginfi insurance pools

Prerequisites

• Node.js (v18 or higher)
• npm (comes with Node.js)
• A Solana wallet with some SOL for transactions
• A private RPC endpoint (see RPC section below)

Setup

1. Clone and Install

git clone https://github.com/nm-de/marginfi_typescript_example.git
cd marginfi_typescript_example
npm install

2. Environment Variables

Create a .env file in the same directory:

# Your Solana wallet private key (base58 encoded)
WALLET_KEY=your_base58_encoded_private_key_here

# Private RPC endpoint (required for reliable marginfi operations)
RPC_URL=https://your-private-rpc-endpoint-here

📡 RPC Endpoint: You need a reliable private RPC endpoint from providers like:

• Helius
• QuickNode
• Alchemy

Public RPCs are too unreliable for MarginFi operations.

3. Run the Application

npm start

Usage

When you run the application, it will:

1. Display Wallet Status: Show your available tokens and their USD values
2. Display MarginFi Status: Show your current lending positions
3. Present Menu Options:
   • Lend SOL
   • Withdraw lent funds
   • Refresh status
   • Exit

Lending Flow

1. Shows available SOL balance
2. Displays current lending APY
3. Asks for amount to lend
4. Shows confirmation with estimated returns
5. Executes the lending transaction on Solana mainnet

Withdrawal Flow

1. Shows all your lending positions
2. Lets you select which pool to withdraw from
3. Asks for withdrawal amount
4. Shows confirmation details
5. Executes the withdrawal transaction on Solana mainnet

mrgnlend Integration Features

✅ Real Transactions: Actual marginfi v2 program interactions on Solana mainnet
✅ Account Management: Automatic marginfi account creation and discovery
✅ SOL Bank Discovery: Finds the SOL lending pool automatically
✅ WSOL Handling: Proper wrapped SOL account management for deposits/withdrawals
✅ Transaction Monitoring: Shows transaction signatures and Solscan links
✅ Zero Fees: 0% platform fees - marginfi only fills insurance pools
✅ Insurance Protection: Your funds are protected by marginfi insurance pools

Technical Implementation

• Program Address: Uses official marginfi v2 program ID MFv2hWf31Z9kbCa1snEPYctwafyhdvnV7FZnsebVacA
• Product: mrgnlend (marginfi v2 lending & borrowing protocol)
• Account Discovery: Finds marginfi groups and SOL banks automatically
• PDA Derivation: Creates proper program-derived addresses for accounts
• Instruction Building: Builds correct marginfi deposit and withdraw instructions
• WSOL Management: Handles wrapped SOL creation and cleanup
• Fee Structure: 0% platform fees as per marginfi documentation

Dependencies

• @mrgnlabs/marginfi-client-v2: Official MarginFi TypeScript SDK
• @solana/web3.js: Solana JavaScript SDK for blockchain interactions
• @mrgnlabs/mrgn-common: MarginFi common utilities and wallet types
• dotenv: Environment variable management
• typescript: TypeScript compiler and type checking
• ts-node: TypeScript execution environment for Node.js

Safety & Testing

⚠️ This application performs real transactions on Solana mainnet

• Start Small: Test with small amounts (0.1 SOL) first
• Verify Transactions: Check the Solscan links before proceeding with larger amounts
• Backup Wallet: Make sure you have your wallet seed phrase backed up
• Monitor Gas: Transactions include priority fees for faster confirmation

Troubleshooting

Common Issues

• "RPC Error": Your RPC endpoint might be unreliable. Try a different private RPC provider.
• "Failed to fetch price": Check your internet connection and RPC endpoint.
• "Insufficient funds": Make sure you have enough SOL for transaction fees (keep ~0.01 SOL for fees).
• "Transaction failed": Increase priority fees or try again with a better RPC endpoint.

Getting Help

• Check transaction details on Solscan
• Verify your wallet has sufficient SOL balance
• Ensure your RPC endpoint is working and has sufficient rate limits

Real Implementation

This TypeScript application performs actual mrgnlend (marginfi v2) protocol interactions:

• ✅ Creates real marginfi accounts on-chain
• ✅ Lends SOL to earn real lending interest in mrgnlend pools
• ✅ Withdraws SOL from your lending positions
• ✅ All transactions are confirmed on Solana mainnet
• ✅ 0% platform fees - marginfi only fills insurance pools
• ✅ Your funds are protected by marginfi insurance pools