🏦 Day 24 of #30DaysOfSolidity — Build a Secure Conditional Payments (Escrow) System in Solidity

The text introduces the concept and implementation of a Secure Escrow System using a Solidity smart contract, designed to facilitate safe, conditional payments in decentralized marketplaces. Functioning as a digital middleman, the contract holds funds until both the buyer and seller fulfill agreed-upon conditions, or until an arbiter resolves a dispute. Key roles include the Buyer (deposits funds), Seller (delivers services/goods), and Arbiter (resolves disagreements). The contract, named Escrow.sol, supports both ETH and ERC-20 tokens, utilizing OpenZeppelin libraries like ReentrancyGuard and SafeERC20 for security. The workflow involves the Buyer creating and funding the escrow, the Seller delivering, and the Buyer approving the release, or the Arbiter stepping in during a dispute to decide on release or refund. Agreements are tracked using an enum Status (e.g., AWAITING_PAYMENT, COMPLETE, DISPUTED). Modifiers such as onlyBuyer, onlySeller, and inStatus enforce access control and proper state transitions. Specialized functions handle funding for ETH and ERC20 tokens, buyer approval, raising disputes, and arbiter resolution. A deadline mechanism allows the seller to claim funds if the buyer remains inactive after the due date. Security practices incorporated include reentrancy protection, safe token transfers, and explicit state checks. Testing is demonstrated using Foundry, outlining test cases for successful ETH escrow flow and ERC20 dispute refunds handled by the arbiter. The system serves as a foundational component for decentralized marketplaces, enabling trustless conditional payments.