Circle’s Smart Contract Platform Enables Seamless ETH to USDC Swaps

Circle’s
Smart
Contract
Platform
now
offers
a
streamlined
method
for
swapping
Ethereum
(ETH)
to
USD
Coin
(USDC)
via
a
smart
contract.
This
development
simplifies
the
process
of
deploying
and
interacting
with
smart
contracts,
leveraging
an
SDK
that
includes
wallet
and
gas
abstraction
infrastructure,
according
to
Circle.com.

Prerequisites

To
use
Circle’s
platform
for
ETH
to
USDC
swaps,
ensure
you
have:

1. 
   Remix
   IDE
   for
   writing
   and
   compiling
   smart
   contracts.
2. 
   Circle
   Web3
   Services
   Account
   for
   managing
   smart
   contract
   interactions.
3. 
   Developer
   Controlled
   Wallet
   for
   deploying
   and
   executing
   contract
   functions.

Writing
the
Smart
Contract

The
smart
contract
interacts
with
Uniswap
to
perform
token
swaps.
When
ETH
is
deposited,
it
is
converted
to
Wrapped
ETH
(WETH),
which
can
be
swapped
for
USDC
using
Uniswap’s
protocol.
Below
is
the
contract
code:

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity ^0.8.20;
import '@uniswap/v3-periphery/contracts/libraries/TransferHelper.sol';
import '@uniswap/v3-periphery/contracts/interfaces/ISwapRouter.sol'; contract SwapExamples { ISwapRouter public immutable swapRouter; address public constant WETH9 = 0x7ceB23fD6bC0adD59E62ac25578270cFf1b9f619; address public constant USDC = 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359; uint24 public constant poolFee = 3000; constructor(ISwapRouter _swapRouter) { swapRouter = _swapRouter; } function swapExactInputSingle(uint256 amountIn) external returns (uint256 amountOut) { TransferHelper.safeTransferFrom(WETH9, msg.sender, address(this), amountIn); TransferHelper.safeApprove(WETH9, address(swapRouter), amountIn); ISwapRouter.ExactInputSingleParams memory params = ISwapRouter.ExactInputSingleParams({ tokenIn: WETH9, tokenOut: USDC, fee: poolFee, recipient: msg.sender, deadline: block.timestamp, amountIn: amountIn, amountOutMinimum: 0, sqrtPriceLimitX96: 0 }); amountOut = swapRouter.exactInputSingle(params); } function swapExactOutputSingle(uint256 amountOut, uint256 amountInMaximum) external returns (uint256 amountIn) { TransferHelper.safeTransferFrom(WETH9, msg.sender, address(this), amountInMaximum); TransferHelper.safeApprove(WETH9, address(swapRouter), amountInMaximum); ISwapRouter.ExactOutputSingleParams memory params = ISwapRouter.ExactOutputSingleParams({ tokenIn: WETH9, tokenOut: USDC, fee: poolFee, recipient: msg.sender, deadline: block.timestamp, amountOut: amountOut, amountInMaximum: amountInMaximum, sqrtPriceLimitX96: 0 }); amountIn = swapRouter.exactOutputSingle(params); if (amountIn < amountInMaximum) { TransferHelper.safeApprove(WETH9, address(swapRouter), 0); TransferHelper.safeTransfer(WETH9, msg.sender, amountInMaximum - amountIn); } }
}

Compiling
the
Smart
Contract

Use
Remix
IDE
to
compile
the
contract
to
obtain
the
ABI
(Application
Binary
Interface)
and
bytecode:

• Create
  a
  new
  file
  in
  Remix
  IDE
  and
  paste
  the
  smart
  contract
  code.
• Select
  the
  appropriate
  Solidity
  compiler
  version
  (0.8.20)
  and
  compile
  the
  contract.
• Copy
  the
  ABI
  JSON
  and
  bytecode
  from
  the “Compilation
  Details”
  section.

Deploying
the
Smart
Contract

Deploy
the
compiled
contract
using
Circle’s
SDK:

npm install @circle-fin/smart-contract-platform @circle-fin/developer-controlled-wallets --save
const circleContractSdk = require('@circle-fin/smart-contract-platform');
const developerControlledWallets = require('@circle-fin/developer-controlled-wallets'); const response = await circleContractSdk.deployContract({ name: 'Swap Contract', description: 'Contract for swapping WETH9 to USDC using Uniswap', walletId: '046b6c7f-0b8a-43b9-b35d-6489e6daee91', blockchain: 'MATIC-AMOY', fee: { type: 'level', config: { feeLevel: 'MEDIUM' } }, constructorParameters: ['0xYourWalletAddress'], entitySecretCiphertext: '0NtD3d3+nmgb4GqYQXzAjKF8h5Zq6sHM2k/...', abiJSON: '[...]', bytecode: '0x...'
});

Upon
successful
deployment,
you
will
receive
a
contractId
and
transactionId
for
reference.

Interacting
with
the
Deployed
Contract

To
perform
token
swaps
using
the
deployed
contract:

const response = await circleDeveloperSdk.createContractExecutionTransaction({ walletId: 'ce714f5b-0d8e-4062-9454-61aa1154869b', contractAddress: '0x2f3A40A3db8a7e3D09B0adfEfbCe4f6F81927557', abiFunctionSignature: 'swapExactInputSingle(uint256)', abiParameters: [1000], fee: { type: 'level', config: { feeLevel: 'MEDIUM' } }
});

Conclusion

Circle’s
Smart
Contract
Platform
provides
an
efficient
solution
for
deploying
and
managing
smart
contracts
to
swap
ETH
to
USDC.
By
leveraging
Circle’s
SDK,
developers
can
easily
execute
transactions
on
the
blockchain.

Source

Image
source:
Shutterstock