Celo DeFi Integration

This skill covers integrating DeFi protocols on Celo, including Uniswap for swaps, Aave for lending/borrowing, and other protocols.

When to Use

• Building swap functionality with Uniswap or Ubeswap
• Integrating lending/borrowing with Aave
• Creating liquidity provision features
• Building DeFi aggregators

DeFi Protocols on Celo

Decentralized Exchanges

Lending & Borrowing

DEX Aggregators

Liquidity & Yield

Uniswap V3 Integration

Contract Addresses - Mainnet (Chain ID: 42220)

Contract Addresses - Alfajores Testnet

Simple Swap Example

import { createWalletClient, custom, encodeFunctionData } from "viem";
import { celo } from "viem/chains";

const SWAP_ROUTER = "0x5615CDAb10dc425a742d643d949a7F474C01abc4";

const SWAP_ROUTER_ABI = [
  {
    name: "exactInputSingle",
    type: "function",
    stateMutability: "payable",
    inputs: [
      {
        name: "params",
        type: "tuple",
        components: [
          { name: "tokenIn", type: "address" },
          { name: "tokenOut", type: "address" },
          { name: "fee", type: "uint24" },
          { name: "recipient", type: "address" },
          { name: "amountIn", type: "uint256" },
          { name: "amountOutMinimum", type: "uint256" },
          { name: "sqrtPriceLimitX96", type: "uint160" },
        ],
      },
    ],
    outputs: [{ type: "uint256" }],
  },
] as const;

async function swapExactInput(
  tokenIn: string,
  tokenOut: string,
  amountIn: bigint,
  amountOutMin: bigint,
  fee: number = 3000
): Promise<string> {
  const walletClient = createWalletClient({
    chain: celo,
    transport: custom(window.ethereum),
  });

  const [address] = await walletClient.getAddresses();

  const hash = await walletClient.sendTransaction({
    account: address,
    to: SWAP_ROUTER,
    data: encodeFunctionData({
      abi: SWAP_ROUTER_ABI,
      functionName: "exactInputSingle",
      args: [
        {
          tokenIn: tokenIn as `0x${string}`,
          tokenOut: tokenOut as `0x${string}`,
          fee,
          recipient: address,
          amountIn,
          amountOutMinimum: amountOutMin,
          sqrtPriceLimitX96: 0n,
        },
      ],
    }),
  });

  return hash;
}

Ubeswap Integration

Celo-native DEX with V2 and V3 support.

Contract Addresses - Mainnet

Aave V3 Integration

Contract Addresses - Mainnet

Supported Assets

Supply Assets

const AAVE_POOL = "0x3E59A31363E2ad014dcbc521c4a0d5757d9f3402";

const POOL_ABI = [
  {
    name: "supply",
    type: "function",
    stateMutability: "nonpayable",
    inputs: [
      { name: "asset", type: "address" },
      { name: "amount", type: "uint256" },
      { name: "onBehalfOf", type: "address" },
      { name: "referralCode", type: "uint16" },
    ],
    outputs: [],
  },
] as const;

async function supplyToAave(asset: string, amount: bigint): Promise<string> {
  const walletClient = createWalletClient({
    chain: celo,
    transport: custom(window.ethereum),
  });

  const [address] = await walletClient.getAddresses();

  // First approve the Pool to spend tokens
  const hash = await walletClient.writeContract({
    address: AAVE_POOL,
    abi: POOL_ABI,
    functionName: "supply",
    args: [asset as `0x${string}`, amount, address, 0],
  });

  return hash;
}

Borrow Assets

const POOL_ABI_BORROW = [
  {
    name: "borrow",
    type: "function",
    stateMutability: "nonpayable",
    inputs: [
      { name: "asset", type: "address" },
      { name: "amount", type: "uint256" },
      { name: "interestRateMode", type: "uint256" },
      { name: "referralCode", type: "uint16" },
      { name: "onBehalfOf", type: "address" },
    ],
    outputs: [],
  },
] as const;

async function borrowFromAave(
  asset: string,
  amount: bigint,
  interestRateMode: number = 2 // 2 = variable rate
): Promise<string> {
  const walletClient = createWalletClient({
    chain: celo,
    transport: custom(window.ethereum),
  });

  const [address] = await walletClient.getAddresses();

  const hash = await walletClient.writeContract({
    address: AAVE_POOL,
    abi: POOL_ABI_BORROW,
    functionName: "borrow",
    args: [asset as `0x${string}`, amount, BigInt(interestRateMode), 0, address],
  });

  return hash;
}

Token Approval

Before interacting with DeFi protocols, approve token spending:

const ERC20_ABI = [
  {
    name: "approve",
    type: "function",
    stateMutability: "nonpayable",
    inputs: [
      { name: "spender", type: "address" },
      { name: "amount", type: "uint256" },
    ],
    outputs: [{ type: "bool" }],
  },
] as const;

async function approveToken(
  token: string,
  spender: string,
  amount: bigint
): Promise<string> {
  const walletClient = createWalletClient({
    chain: celo,
    transport: custom(window.ethereum),
  });

  const [address] = await walletClient.getAddresses();

  const hash = await walletClient.writeContract({
    address: token as `0x${string}`,
    abi: ERC20_ABI,
    functionName: "approve",
    args: [spender as `0x${string}`, amount],
  });

  return hash;
}

Fee Tiers (Uniswap V3)

Dependencies

{
  "dependencies": {
    "viem": "^2.0.0"
  }
}

For Aave integration:

{
  "dependencies": {
    "@bgd-labs/aave-address-book": "^4.0.0"
  }
}

Additional Resources

• contract-addresses.md - All DeFi contract addresses