Lido

Lido is the largest liquid staking protocol on Ethereum. Users deposit ETH and receive stETH, a rebasing token whose balance increases daily as staking rewards accrue. wstETH is the non-rebasing wrapper used in DeFi. The protocol manages a validator set, an oracle-reported share rate, and an on-chain withdrawal queue.

What You Probably Got Wrong

• stETH is a rebasing token — Your stETH balance changes every day when the oracle reports. If you store a balance in a variable and check it later, it will differ. This breaks naive accounting in smart contracts. Use wstETH or track shares, not balances.
• wstETH is NOT stETH — wstETH is a non-rebasing ERC-20 wrapper around stETH shares. 1 wstETH != 1 stETH. The exchange rate drifts upward over time as rewards accumulate. Always convert via stETH.getPooledEthByShares() or wstETH.stEthPerToken().
• stETH/ETH is NOT 1:1 — There is a market rate on secondary markets (Curve, Uniswap) that can deviate from the protocol's internal rate, especially during high withdrawal demand or market stress. The 2022 depeg hit ~0.93.
• stETH transfers lose 1-2 wei — Due to shares-to-balance rounding, transferring your full balanceOf may leave 1-2 wei behind. The recipient may receive 1 wei less than amount. This is by design, not a bug. Never assert exact equality on stETH transfers.
• Withdrawals are NOT instant — The withdrawal queue processes requests in order. Finalization depends on validator exits and oracle reports. Typical wait: 1-5 days, but can be longer during high demand. You must request, wait for finalization, then claim in a separate tx.
• Shares are the canonical unit — stETH balances are derived from shares. balanceOf(account) = shares[account] * totalPooledEther / totalShares. All internal accounting uses shares. When integrating, think in shares.
• submit() requires the referral address parameter — The staking function is submit(address _referral) payable, not just a payable fallback. Pass address(0) if you have no referral.

Quick Start

Stake ETH via Lido (TypeScript)

import { createPublicClient, createWalletClient, http, parseAbi, parseEther } from "viem";
import { mainnet } from "viem/chains";
import { privateKeyToAccount } from "viem/accounts";
 
const LIDO = "0xae7ab96520DE3A18E5e111B5EaAb095312D7fE84" as const;
 
const LIDO_ABI = parseAbi([
  "function submit(address _referral) external payable returns (uint256)",
  "function balanceOf(address _account) external view returns (uint256)",
  "function sharesOf(address _account) external view returns (uint256)",
  "function getPooledEthByShares(uint256 _sharesAmount) external view returns (uint256)",
  "function getSharesByPooledEth(uint256 _ethAmount) external view returns (uint256)",
  "function getTotalPooledEther() external view returns (uint256)",
  "function getTotalShares() external view returns (uint256)",
]);
 
const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);
 
const publicClient = createPublicClient({
  chain: mainnet,
  transport: http(process.env.RPC_URL),
});
 
const walletClient = createWalletClient({
  account,
  chain: mainnet,
  transport: http(process.env.RPC_URL),
});
 
async function stakeEth(amountEth: string) {
  const { request } = await publicClient.simulateContract({
    address: LIDO,
    abi: LIDO_ABI,
    functionName: "submit",
    args: ["0x0000000000000000000000000000000000000000"],
    value: parseEther(amountEth),
    account,
  });
 
  const hash = await walletClient.writeContract(request);
  const receipt = await publicClient.waitForTransactionReceipt({ hash });
  if (receipt.status !== "success") throw new Error("Stake tx reverted");
 
  return hash;
}

Staking

Submit ETH, Receive stETH (Solidity)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;
 
interface ILido {
    function submit(address _referral) external payable returns (uint256 sharesAmount);
    function balanceOf(address _account) external view returns (uint256);
    function sharesOf(address _account) external view returns (uint256);
    function getPooledEthByShares(uint256 _sharesAmount) external view returns (uint256);
    function getSharesByPooledEth(uint256 _ethAmount) external view returns (uint256);
    function transferShares(address _recipient, uint256 _sharesAmount) external returns (uint256);
}
 
contract LidoStaker {
    ILido public constant LIDO = ILido(0xae7ab96520DE3A18E5e111B5EaAb095312D7fE84);
 
    event Staked(address indexed user, uint256 ethAmount, uint256 sharesReceived);
 
    /// @notice Stake ETH via Lido. Returns shares minted, not stETH amount.
    function stake() external payable returns (uint256 shares) {
        if (msg.value == 0) revert ZeroDeposit();
 
        shares = LIDO.submit{value: msg.value}(address(0));
        emit Staked(msg.sender, msg.value, shares);
    }
 
    /// @notice Transfer stETH using shares to avoid rounding issues
    /// @dev transferShares is exact — no 1-2 wei rounding loss
    function transferSharesTo(address recipient, uint256 sharesAmount) external {
        LIDO.transferShares(recipient, sharesAmount);
    }
 
    error ZeroDeposit();
}

Wrap stETH to wstETH

wstETH holds a fixed number of stETH shares. Its balance does not rebase. Use wstETH in DeFi protocols, vaults, and any contract that stores balances.

const WSTETH = "0x7f39C581F595B53c5cb19bD0b3f8dA6c935E2Ca0" as const;
 
const WSTETH_ABI = parseAbi([
  "function wrap(uint256 _stETHAmount) external returns (uint256)",
  "function unwrap(uint256 _wstETHAmount) external returns (uint256)",
  "function getStETHByWstETH(uint256 _wstETHAmount) external view returns (uint256)",
  "function getWstETHByStETH(uint256 _stETHAmount) external view returns (uint256)",
  "function stEthPerToken() external view returns (uint256)",
  "function tokensPerStEth() external view returns (uint256)",
]);
 
async function wrapSteth(stEthAmount: bigint) {
  // Approve stETH spending by wstETH contract first
  const approveHash = await walletClient.writeContract({
    address: LIDO,
    abi: parseAbi(["function approve(address spender, uint256 amount) external returns (bool)"]),
    functionName: "approve",
    args: [WSTETH, stEthAmount],
  });
  await publicClient.waitForTransactionReceipt({ hash: approveHash });
 
  const { request } = await publicClient.simulateContract({
    address: WSTETH,
    abi: WSTETH_ABI,
    functionName: "wrap",
    args: [stEthAmount],
    account,
  });
 
  const hash = await walletClient.writeContract(request);
  const receipt = await publicClient.waitForTransactionReceipt({ hash });
  if (receipt.status !== "success") throw new Error("Wrap tx reverted");
 
  return hash;
}
 
async function unwrapWsteth(wstEthAmount: bigint) {
  const { request } = await publicClient.simulateContract({
    address: WSTETH,
    abi: WSTETH_ABI,
    functionName: "unwrap",
    args: [wstEthAmount],
    account,
  });
 
  const hash = await walletClient.writeContract(request);
  const receipt = await publicClient.waitForTransactionReceipt({ hash });
  if (receipt.status !== "success") throw new Error("Unwrap tx reverted");
 
  return hash;
}

Wrap/Unwrap in Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;
 
import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 
interface IWstETH {
    function wrap(uint256 _stETHAmount) external returns (uint256);
    function unwrap(uint256 _wstETHAmount) external returns (uint256);
    function getStETHByWstETH(uint256 _wstETHAmount) external view returns (uint256);
    function getWstETHByStETH(uint256 _stETHAmount) external view returns (uint256);
}
 
contract WstETHWrapper {
    IERC20 public constant STETH = IERC20(0xae7ab96520DE3A18E5e111B5EaAb095312D7fE84);
    IWstETH public constant WSTETH = IWstETH(0x7f39C581F595B53c5cb19bD0b3f8dA6c935E2Ca0);
 
    /// @notice Wrap stETH to wstETH. Caller must approve this contract for stETH first.
    function wrapStETH(uint256 stETHAmount) external returns (uint256 wstETHReceived) {
        STETH.transferFrom(msg.sender, address(this), stETHAmount);
        // Rounding may cause actual transferred amount to differ by 1-2 wei
        uint256 actualBalance = STETH.balanceOf(address(this));
        STETH.approve(address(WSTETH), actualBalance);
        wstETHReceived = WSTETH.wrap(actualBalance);
        IERC20(address(WSTETH)).transfer(msg.sender, wstETHReceived);
    }
 
    error InsufficientBalance();
}

Withdrawals

Lido v2 introduced an on-chain withdrawal queue. Withdrawals mint an NFT (ERC-721) representing the request. Once finalized by the oracle, the NFT can be claimed for ETH.

Request Withdrawal (TypeScript)

const WITHDRAWAL_QUEUE = "0x889edC2eDab5f40e902b864aD4d7AdE8E412F9B1" as const;
 
const WITHDRAWAL_ABI = parseAbi([
  "function requestWithdrawals(uint256[] _amounts, address _owner) external returns (uint256[])",
  "function requestWithdrawalsWstETH(uint256[] _amounts, address _owner) external returns (uint256[])",
  "function claimWithdrawals(uint256[] _requestIds, uint256[] _hints) external",
  "function getWithdrawalStatus(uint256[] _requestIds) external view returns ((uint256 amountOfStETH, uint256 amountOfShares, address owner, uint256 timestamp, bool isFinalized, bool isClaimed)[])",
  "function findCheckpointHints(uint256[] _requestIds, uint256 _firstIndex, uint256 _lastIndex) external view returns (uint256[])",
  "function getLastCheckpointIndex() external view returns (uint256)",
  "function getLastFinalizedRequestId() external view returns (uint256)",
]);
 
async function requestWithdrawal(stEthAmounts: bigint[]) {
  // Approve WithdrawalQueue to spend stETH
  const totalAmount = stEthAmounts.reduce((a, b) => a + b, 0n);
  const approveHash = await walletClient.writeContract({
    address: LIDO,
    abi: parseAbi(["function approve(address spender, uint256 amount) external returns (bool)"]),
    functionName: "approve",
    args: [WITHDRAWAL_QUEUE, totalAmount],
  });
  await publicClient.waitForTransactionReceipt({ hash: approveHash });
 
  const { request } = await publicClient.simulateContract({
    address: WITHDRAWAL_QUEUE,
    abi: WITHDRAWAL_ABI,
    functionName: "requestWithdrawals",
    args: [stEthAmounts, account.address],
    account,
  });
 
  const hash = await walletClient.writeContract(request);
  const receipt = await publicClient.waitForTransactionReceipt({ hash });
  if (receipt.status !== "success") throw new Error("Withdrawal request reverted");
 
  return hash;
}

Check Withdrawal Status and Claim

async function getWithdrawalStatus(requestIds: bigint[]) {
  const statuses = await publicClient.readContract({
    address: WITHDRAWAL_QUEUE,
    abi: WITHDRAWAL_ABI,
    functionName: "getWithdrawalStatus",
    args: [requestIds],
  });
 
  return statuses.map((s, i) => ({
    requestId: requestIds[i],
    amountOfStETH: s.amountOfStETH,
    isFinalized: s.isFinalized,
    isClaimed: s.isClaimed,
    owner: s.owner,
  }));
}
 
async function claimWithdrawals(requestIds: bigint[]) {
  const lastCheckpointIndex = await publicClient.readContract({
    address: WITHDRAWAL_QUEUE,
    abi: WITHDRAWAL_ABI,
    functionName: "getLastCheckpointIndex",
  });
 
  const hints = await publicClient.readContract({
    address: WITHDRAWAL_QUEUE,
    abi: WITHDRAWAL_ABI,
    functionName: "findCheckpointHints",
    args: [requestIds, 1n, lastCheckpointIndex],
  });
 
  const { request } = await publicClient.simulateContract({
    address: WITHDRAWAL_QUEUE,
    abi: WITHDRAWAL_ABI,
    functionName: "claimWithdrawals",
    args: [requestIds, hints],
    account,
  });
 
  const hash = await walletClient.writeContract(request);
  const receipt = await publicClient.waitForTransactionReceipt({ hash });
  if (receipt.status !== "success") throw new Error("Claim tx reverted");
 
  return hash;
}

Reading Protocol State

Share Rate, Total Pooled Ether, APR Estimation

async function getProtocolState() {
  const [totalPooledEther, totalShares] = await Promise.all([
    publicClient.readContract({
      address: LIDO,
      abi: LIDO_ABI,
      functionName: "getTotalPooledEther",
    }),
    publicClient.readContract({
      address: LIDO,
      abi: LIDO_ABI,
      functionName: "getTotalShares",
    }),
  ]);
 
  // Share rate: how much ETH one share is worth (18 decimals)
  const shareRate = (totalPooledEther * 10n ** 18n) / totalShares;
 
  return { totalPooledEther, totalShares, shareRate };
}
 
async function convertWstethToSteth(wstEthAmount: bigint): Promise<bigint> {
  return publicClient.readContract({
    address: WSTETH,
    abi: WSTETH_ABI,
    functionName: "getStETHByWstETH",
    args: [wstEthAmount],
  });
}
 
async function convertStethToWsteth(stEthAmount: bigint): Promise<bigint> {
  return publicClient.readContract({
    address: WSTETH,
    abi: WSTETH_ABI,
    functionName: "getWstETHByStETH",
    args: [stEthAmount],
  });
}

Reading Share Rate in Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;
 
interface ILido {
    function getTotalPooledEther() external view returns (uint256);
    function getTotalShares() external view returns (uint256);
    function getPooledEthByShares(uint256 _sharesAmount) external view returns (uint256);
    function getSharesByPooledEth(uint256 _ethAmount) external view returns (uint256);
}
 
contract LidoReader {
    ILido public constant LIDO = ILido(0xae7ab96520DE3A18E5e111B5EaAb095312D7fE84);
 
    /// @notice Returns ETH value of one stETH share, scaled to 18 decimals
    function getShareRate() external view returns (uint256) {
        return LIDO.getPooledEthByShares(1e18);
    }
 
    /// @notice Convert stETH amount to underlying shares
    function ethToShares(uint256 ethAmount) external view returns (uint256) {
        return LIDO.getSharesByPooledEth(ethAmount);
    }
 
    /// @notice Convert shares to stETH amount
    function sharesToEth(uint256 sharesAmount) external view returns (uint256) {
        return LIDO.getPooledEthByShares(sharesAmount);
    }
}

DeFi Integration

wstETH as Collateral (Aave/Compound Pattern)

When integrating wstETH in lending protocols or vaults, always use wstETH (not stETH) to avoid rebasing accounting complexity.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;
 
import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 
interface IWstETH {
    function getStETHByWstETH(uint256 _wstETHAmount) external view returns (uint256);
}
 
/// @notice Simplified vault accepting wstETH as collateral
/// @dev Uses wstETH to avoid rebasing — balanceOf is stable between oracle reports
contract WstETHVault {
    IERC20 public constant WSTETH = IERC20(0x7f39C581F595B53c5cb19bD0b3f8dA6c935E2Ca0);
    IWstETH public constant WSTETH_RATE = IWstETH(0x7f39C581F595B53c5cb19bD0b3f8dA6c935E2Ca0);
 
    mapping(address => uint256) public deposits;
 
    event Deposited(address indexed user, uint256 wstETHAmount);
    event Withdrawn(address indexed user, uint256 wstETHAmount);
 
    function deposit(uint256 wstETHAmount) external {
        WSTETH.transferFrom(msg.sender, address(this), wstETHAmount);
        deposits[msg.sender] += wstETHAmount;
        emit Deposited(msg.sender, wstETHAmount);
    }
 
    function withdraw(uint256 wstETHAmount) external {
        if (deposits[msg.sender] < wstETHAmount) revert InsufficientDeposit();
        deposits[msg.sender] -= wstETHAmount;
        WSTETH.transfer(msg.sender, wstETHAmount);
        emit Withdrawn(msg.sender, wstETHAmount);
    }
 
    /// @notice Get the ETH value of a user's wstETH collateral
    function getCollateralValueInEth(address user) external view returns (uint256) {
        return WSTETH_RATE.getStETHByWstETH(deposits[user]);
    }
 
    error InsufficientDeposit();
}

Oracle Considerations for wstETH Pricing

wstETH price = wstETH/stETH exchange rate * stETH/ETH rate * ETH/USD price. Protocols typically use:

1. Chainlink wstETH/ETH feed — Available on mainnet at 0x536218f9E9Eb48863970252233c8F271f554C2d0. Combines the protocol rate with market data.
2. On-chain rate from wstETH contract — wstETH.stEthPerToken() gives the protocol exchange rate. This does NOT reflect secondary market deviations.
3. Dual oracle approach — Use the Chainlink feed as primary, fall back to the on-chain rate with bounds checking.

const WSTETH_ETH_FEED = "0x536218f9E9Eb48863970252233c8F271f554C2d0" as const;
 
const AGGREGATOR_ABI = parseAbi([
  "function latestRoundData() external view returns (uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound)",
  "function decimals() external view returns (uint8)",
]);
 
async function getWstethEthPrice() {
  const [roundData, decimals] = await Promise.all([
    publicClient.readContract({
      address: WSTETH_ETH_FEED,
      abi: AGGREGATOR_ABI,
      functionName: "latestRoundData",
    }),
    publicClient.readContract({
      address: WSTETH_ETH_FEED,
      abi: AGGREGATOR_ABI,
      functionName: "decimals",
    }),
  ]);
 
  const [, answer, , updatedAt] = roundData;
  if (answer <= 0n) throw new Error("Invalid wstETH/ETH price");
 
  const now = BigInt(Math.floor(Date.now() / 1000));
  // wstETH/ETH feed heartbeat: 86400s
  if (now - updatedAt > 86400n) throw new Error("Stale wstETH/ETH price");
 
  return { answer, decimals };
}

Contract Addresses

Last verified: 2025-05-01

Ethereum Mainnet

wstETH on L2s

Chainlink Price Feeds for stETH/wstETH

Error Handling

Security Considerations

Rebasing Accounting

stETH balances change on every oracle report (typically daily). Smart contracts that store stETH balances in mappings will have stale values. Two safe patterns:

1. Use wstETH — Non-rebasing. Balance is stable. This is the correct choice for vaults, collateral, and any stored-balance pattern.
2. Track shares — Use sharesOf() and getPooledEthByShares() instead of balanceOf(). Shares are the invariant unit.

The 1-2 Wei Rounding Issue

stETH transfer(to, amount) converts amount to shares (rounding down), then converts back to balance for the recipient (rounding down again). The sender's balance decreases by amount, but the recipient may receive amount - 1 or amount - 2 wei. This is inherent to the rebasing design.

Implications:

• Never use require(balanceAfter - balanceBefore == amount) with stETH
• Use transferShares() when exact amounts matter
• Tolerance of 2 wei on stETH balance checks

Oracle Manipulation Risks

• The stETH/ETH Chainlink feed reflects market price, which can deviate from the protocol rate during market stress
• The on-chain stEthPerToken() rate is controlled by the Lido oracle — it can only change once per oracle report cycle and is bounded by sanity checks
• For highest security, cross-check the Chainlink feed against the on-chain rate and revert if deviation exceeds a threshold (e.g., 5%)

/// @notice Revert if Chainlink wstETH/ETH deviates too far from on-chain rate
function validateOracleRate(int256 chainlinkAnswer, uint8 feedDecimals) internal view {
    uint256 onchainRate = IWstETH(0x7f39C581F595B53c5cb19bD0b3f8dA6c935E2Ca0).stEthPerToken();
    uint256 normalizedChainlink = feedDecimals <= 18
        ? uint256(chainlinkAnswer) * 10 ** (18 - feedDecimals)
        : uint256(chainlinkAnswer) / 10 ** (feedDecimals - 18);
 
    uint256 deviation = normalizedChainlink > onchainRate
        ? normalizedChainlink - onchainRate
        : onchainRate - normalizedChainlink;
 
    // 5% max deviation threshold
    if (deviation * 100 / onchainRate > 5) revert OracleDeviation();
}

Integration Checklist

1. Use wstETH (not stETH) in any contract that stores balances
2. Never assert exact stETH transfer amounts — allow 2 wei tolerance
3. Check Chainlink feed staleness with per-feed heartbeat
4. Cross-validate oracle price against on-chain rate for critical paths
5. Handle withdrawal queue delays in UX — show estimated wait time
6. Test with a forked mainnet (anvil --fork-url) to verify rebase behavior

References

• Lido Docs
• Lido Deployed Contracts
• stETH Integration Guide
• wstETH on L2s
• Lido GitHub
• Withdrawal Queue Docs
• Chainlink stETH/ETH Feed