approve

Standard ERC-20 approval for vault shares. Use this only if you want a third party to call transferFrom, withdraw, or redeem on your shares.

WARNING

This is not the USDC approval. To deposit, you approve USDC to the vault - see Getting Started -> Approving USDC.

Signature

function approve(address spender, uint256 value) external returns (bool);

Parameters

Name	Type	Description
spender	address	Address allowed to spend the caller's shares.
value	uint256	Allowance in share base units (18 decimals). Use 2^256 - 1 for unlimited.

Returns

true on success. (The function reverts on failure rather than returning false.)

Events emitted

event Approval(address indexed owner, address indexed spender, uint256 value);

Example — approve a router for unlimited share spending

import { maxUint256 } from 'viem'
import { publicClient, walletClient } from './client'
import { liteUsdVaultAbi } from './abi'
import { VAULT } from './constants'

const ROUTER = '0x...' as const

const { request } = await publicClient.simulateContract({
  account: walletClient.account!,
  address: VAULT,
  abi: liteUsdVaultAbi,
  functionName: 'approve',
  args: [ROUTER, maxUint256],
})

const hash = await walletClient.writeContract(request)
await publicClient.waitForTransactionReceipt({ hash })

Notes

• Reapproving overwrites the existing allowance — it does not add to it.
• Some integrations recommend setting allowance to 0 first before raising it from a non-zero value, to defend against the classic ERC-20 race condition. The vault uses the standard OpenZeppelin implementation, so this is optional but harmless.