security

Prevent reentrancy by following the Checks-Effects-Interactions pattern: validate inputs, update all state, then make external calls last. Add OpenZeppelin's ReentrancyGuard with the nonReentrant modifier on external-calling functions as a safety net.

Use Chainlink price feeds with staleness and validity checks rather than DEX spot prices, which flash loans can manipulate in one transaction. If onchain data is required, use Uniswap V3 TWAP over 30+ minutes.

UUPS is recommended by OpenZeppelin because it costs less gas per call and places upgrade logic in the implementation. Always use initializer functions instead of constructors, disable initializers on the implementation, and transfer upgrade authority to a multisig.

USDT does not return a bool on transfer and approve, so standard IERC20 calls revert even on success. Use OpenZeppelin's SafeERC20 library with safeTransfer and safeApprove to handle non-standard token implementations.

Never approve type(uint256).max, because an exploited contract with infinite approval can drain your entire token balance. Approve only the exact amount needed or a small bounded multiple for repeated interactions.