How does Ethereum's EVM (Ethereum Virtual Machine) work?

The Ethereum Virtual Machine (EVM) is the sandboxed runtime environment that executes smart contract bytecode on every Ethereum node. Key characteristics: (1) Stack-based — the EVM uses a 1024-element stack (with 32-byte/256-bit words) for computation, not registers; (2) Deterministic — same input always produces same output across all nodes; this is critical for consensus; (3) Sandboxed — smart contracts can't access the file system, network, or external APIs without oracles; (4) Gas metered — every opcode costs a defined amount of gas (e.g., ADD = 3 gas, SLOAD = 100-2100 gas); (5) Memory model — three data areas: stack (function execution), memory (temporary byte array, reset each call), storage (persistent key-value store on the blockchain); (6) EVM compatibility — many blockchains (Polygon, BSC, Arbitrum, Optimism, Avalanche C-Chain) implement the EVM, allowing Ethereum smart contracts to deploy with minimal changes. Solidity code → Solidity compiler → EVM bytecode → deployed on chain → EVM on each node executes it.