Smart Contract Backend

Smart contracts are the dApp backend — immutable programs that define rules for transfers, swaps, voting, and more. Solidity on Ethereum and EVM chains dominates; Rust powers Solana and NEAR, while Move runs on Aptos and Sui.

Contracts hold token balances, enforce business logic without intermediaries, emit events for indexers, and expose read functions for live state queries. Use OpenZeppelin libraries for battle-tested patterns and get professional audits for anything holding significant value.

Bugs at scale are irreversible. See the Smart Contracts 101 and Solidity Programming courses for language depth, security patterns, and gas optimization — this chapter focuses on how contracts fit into the broader dApp stack.