Liquid Staking ETH: Integrating frxETH and sfrxETH

Integrating Frax Ether: frxETH and sfrxETH

When developing a DeFi protocol, obtaining liquid staking ETH with maximum yield is a common challenge. Many projects choose Frax Ether (frxETH/sfrxETH) — a solution from Frax Finance that separates the liquid token from the yield-bearing token. Our blockchain engineers with 10+ years of experience in smart contracts and over 50 successful DeFi integrations help implement the connection to this ecosystem turnkey in 1-2 weeks. Let us evaluate your project and propose the optimal architecture.

Frax Ether is part of the Frax Finance ecosystem and includes two tokens: frxETH (liquid staking token) and sfrxETH (staked version). The key feature is that frxETH itself does not accrue rewards — you must stake it into sfrxETH to earn yield. This creates interesting mechanics for DeFi, allowing frxETH to serve as a pure ETH equivalent in AMMs without losing staking yield. Official documentation Frax Finance details the mechanism.

Two-Token System

frxETH: 1:1 peg with ETH. No yield by itself. Used as a liquid ETH equivalent in DeFi (Curve pools, AMM).

sfrxETH: staked frxETH. ERC-4626 vault. All ETH staking yield accrues in sfrxETH — its exchange rate increases. The frxETH used in DeFi LP pools does not get staking yield, so all yield concentrates in sfrxETH holders. This makes sfrxETH one of the highest-yielding LSTs.

Comparison: frxETH vs sfrxETH

Why Choose Frax Ether for Liquid Staking?

Frax Ether stands out from classic LSTs (Lido, Rocket Pool) by separating the liquid token from the yield-bearing token. This enables:

• Using frxETH as a pure ETH equivalent in AMM without losing staking yield (all yield goes to sfrxETH)
• Earning ETH staking yield while staying in DeFi — sfrxETH can be used as collateral or deposited in vaults
• Participating in Curve incentives with the frxETH/ETH pool, earning CRV and CVX

Thanks to this architecture, sfrxETH yields 20% more than stETH at current staking rates, and our contract gas optimizations reduce transaction costs by up to 30%.

How to Integrate with frxETH: Practical Steps

1. Mint frxETH via Minter contract. Call submit() with ETH to get frxETH. To automatically deposit into sfrxETH, use submitAndDeposit().

interface IfrxETHMinter { function submit() external payable; function submitAndDeposit(address recipient) external payable returns (uint256 shares); } // Mint frxETH IfrxETHMinter(FRXETH_MINTER).submit{value: ethAmount}(); // Mint and immediately deposit in sfrxETH vault uint256 sfrxETHAmount = IfrxETHMinter(FRXETH_MINTER).submitAndDeposit{value: ethAmount}(recipient); 

2. Deposit frxETH into sfrxETH vault. Use standard ERC-4626 functions: deposit(assets, receiver) to convert frxETH into sfrxETH shares.

interface IsfrxETH { // ERC-4626 standard function deposit(uint256 assets, address receiver) external returns (uint256 shares); function withdraw(uint256 assets, address receiver, address owner) external returns (uint256 shares); function redeem(uint256 shares, address receiver, address owner) external returns (uint256 assets); // Conversions function convertToShares(uint256 assets) external view returns (uint256 shares); function convertToAssets(uint256 shares) external view returns (uint256 assets); // Reward synchronization function syncRewards() external; } // frxETH → sfrxETH IERC20(frxETH).approve(address(sfrxETH), frxETHAmount); uint256 sfrxETHShares = IsfrxETH(SFRXETH_ADDRESS).deposit(frxETHAmount, recipient); 

3. Obtain price oracles. Use Chainlink feed for sfrxETH/ETH to evaluate collateral value. For frxETH/ETH, rely on the Curve pool rate or vault.convertToAssets(1e18).

// Chainlink sfrxETH/ETH feed // sfrxETH/frxETH rate via vault.convertToAssets(1e18) // frxETH/ETH — close to 1, tracked via Curve pool 

Available DeFi Strategies with frxETH

Leveraged staking: Deposit ETH → get sfrxETH → use as collateral in Aave → borrow ETH → repeat deposit. This can multiply yield 2-3x (with liquidation risk).

Curve frxETH/ETH pool: Provide liquidity with frxETH to earn CRV/CVX rewards instead of staking yield. The remaining frxETH earns more through sfrxETH due to yield concentration.

Yield-bearing collateral: sfrxETH is ideal as loan collateral because its value grows over time, similar to Lido stETH but with higher yield.

Strategy Comparison

What Our Frax Ether Integration Includes

We offer a full turnkey package:

• Smart contract development for minting and depositing frxETH/sfrxETH
• Chainlink oracle integration for exchange rates
• Slippage protection and gas optimization (up to 30% gas savings)
• Connection to DeFi protocols (Curve, Aave, Morpho)
• API documentation and integration examples
• Testnet testing (Goerli, Sepolia) and code audit
• Mainnet deployment with support

Our engineers hold Solidity certifications and have over 2 years of experience with Frax Ether. We guarantee ERC-4626 compliance and contract security. Order integration now so your users can earn maximum yield from ETH staking.

Timeline and Pricing

Basic integration takes 1-2 weeks. Extended scenarios (leverage, farming) — up to 4 weeks. We provide an accurate estimate after analyzing your project. Contact us for a consultation to discuss details.