/marginfi

name: marginfi
description: Complete guide for Marginfi - Solana's decentralized lending protocol for lending, borrowing, leveraged positions(looping) and flash loans. Covers account creation, deposits, borrows, repayments, withdrawals, flash loans, and leveraged positions using the @mrgnlabs/marginfi-client-v2 SDK.

Marginfi Development Guide

Build lending and borrowing applications on Solana with Marginfi - a decentralized, overcollateralized lending protocol offering deposits, borrows, flash loans, and leveraged positions.

Overview

Marginfi provides:

• **Lending & Borrowing**: Deposit collateral to earn yield, borrow against your deposits
• **Multiple Accounts**: Create multiple accounts per wallet with independent positions
• **Risk Management**: Advanced health calculations using asset and liability weights
• **Flash Loans**: Atomic, uncollateralized lending within a single transaction
• **Looping**: Leverage positions by depositing and borrowing in a single transaction
• **Multi-Asset Support**: SOL, USDC, LSTs (JitoSOL, mSOL), and more

Quick Start

Installation

# Marginfi client SDK
npm install @mrgnlabs/marginfi-client-v2

# Common utilities
npm install @mrgnlabs/mrgn-common

# Required peer dependencies
npm install @solana/web3.js @coral-xyz/anchor

Environment Setup

# .env file
SOLANA_RPC_URL=https://api.mainnet-beta.solana.com
WALLET_KEYPAIR_PATH=./keypair.json

Marginfi SDK (marginfi-client-v2)

The SDK enables interaction with Marginfi's lending protocol for deposits, borrows, repayments, withdrawals, and advanced operations.

Core Classes

| Class | Purpose | |-------|---------| | `MarginfiClient` | Main client for loading groups and banks | | `MarginfiAccountWrapper` | User account management and lending operations | | `Bank` | Individual lending pool configuration and state | | `Balance` | Asset or liability position within an account | | `NodeWallet` | Wallet adapter for server-side usage |

Initialize Client

import { MarginfiClient, getConfig } from "@mrgnlabs/marginfi-client-v2";
import { NodeWallet } from "@mrgnlabs/mrgn-common";
import { Connection, Keypair } from "@solana/web3.js";

const connection = new Connection("https://api.mainnet-beta.solana.com");
const keypair = Keypair.fromSecretKey(/* your secret key */);
const wallet = new NodeWallet(keypair);

// Get production configuration
const config = getConfig("production");

// Load Marginfi client
const client = await MarginfiClient.fetch(config, wallet, connection);

// Access banks
for (const [address, bank] of client.banks) {
  console.log(`${bank.tokenSymbol}: ${address}`);
}

Get Bank by Token

// Get bank by token symbol
const solBank = client.getBankByTokenSymbol("SOL");
const usdcBank = client.getBankByTokenSymbol("USDC");

// Get bank by mint address
const usdcMint = new PublicKey("EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v");
const usdcBankByMint = client.getBankByMint(usdcMint);

// Get bank by public key
const bank = client.getBankByPk(new PublicKey("..."));

Create Account

// Create a new Marginfi account
const account = await client.createMarginfiAccount();

console.log("Account address:", account.address.toBase58());
console.log("Authority:", account.authority.toBase58());

Fetch Existing Accounts

// Get all accounts for a wallet
const accounts = await client.getMarginfiAccountsForAuthority(wallet.publicKey);

for (const account of accounts) {
  console.log("Account:", account.address.toBase58());
  console.log("Active balances:", account.activeBalances.length);
  
  // Check positions
  for (const balance of account.activeBalances) {
    const bank = client.getBankByPk(balance.bankPk);
    const quantity = balance.computeQuantityUi(bank!);
    console.log(`  ${bank?.tokenSymbol}: Assets=${quantity.assets}, Liabilities=${quantity.liabilities}`);
  }
}

Deposit Collateral

async function deposit(
  account: MarginfiAccountWrapper,
  client: MarginfiClient,
  tokenSymbol: string,
  amount: number // UI-denominated amount (tokens, e.g., 1 for 1 SOL)
) {
  const bank = client.getBankByTokenSymbol(tokenSymbol);
  if (!bank) throw new Error(`Bank ${tokenSymbol} not found`);

  // Execute deposit
  const signature = await account.deposit(amount, bank.address);
  
  console.log("Deposit signature:", signature);
  return signature;
}

// Example: Deposit 1 SOL
await deposit(account, client, "SOL", 1);

Borrow Assets

async function borrow(
  account: MarginfiAccountWrapper,
  client: MarginfiClient,
  tokenSymbol: string,
  amount: number
) {
  const bank = client.getBankByTokenSymbol(tokenSymbol);
  if (!bank) throw new Error(`Bank ${tokenSymbol} not found`);

  // Execute borrow
    const signature = await account.borrow(amount, bank.address);
  
  console.log("Borrow signature:", signature);
  return signature;
}

// Example: Borrow 100 USDC
await borrow(account, client, "USDC", 100);

Repay Debt

async function repay(
  account: MarginfiAccountWrapper,
  client: MarginfiClient,
  tokenSymbol: string,
  amount: number,
  repayAll: boolean = false
) {
  const bank = client.getBankByTokenSymbol(tokenSymbol);
  if (!bank) throw new Error(`Bank ${tokenSymbol} not found`);

  // Execute repay
  const signature = await account.repay(amount, bank.address, repayAll);
  
  console.log("Repay signature:", signature);
  return signature;
}

// Partial repay
await repay(account, client, "USDC", 50);

// Repay all (handles accrued interest)
await repay(account, client, "USDC", 0, true);

Withdraw Collateral

async function withdraw(
  account: MarginfiAccountWrapper,
  client: MarginfiClient,
  tokenSymbol: string,
  amount: number,
  withdrawAll: boolean = false
) {
  const bank = client.getBankByTokenSymbol(tokenSymbol);
  if (!bank) throw new Error(`Bank ${tokenSymbol} not found`