Ethereum Foundations: Accounts, Gas, the EVM, and Smart Contract Execution
Understand the account-based model and programmable execution environment that made smart contracts widely accessible.
Inside this chapter
- Ethereum Account Model
- Gas, Fees, and Computation
- The EVM and Contract Execution
- A Simple Contract Example
Series navigation
Study the chapters in order for the smoothest path from beginner blockchain concepts to advanced architecture and production practices. Use the navigation at the bottom of each page to move chapter by chapter.
Ethereum Account Model
Ethereum uses an account-based model rather than the UTXO model. Externally owned accounts are controlled by private keys, while contract accounts are controlled by deployed smart-contract code. Each account has fields such as balance, nonce, and in the case of contracts, bytecode and storage.
Gas, Fees, and Computation
Because Ethereum supports programmable execution, every operation has a gas cost. Gas measures computation and storage-related effort. Users specify fee parameters, and the network executes transactions only if enough gas is available. This prevents infinite loops and helps allocate scarce block resources.
transaction fee = gas used x effective gas priceStudents should understand that expensive on-chain storage and loops are design concerns, not just billing details.
The EVM and Contract Execution
The Ethereum Virtual Machine is the runtime environment that executes smart-contract bytecode on every validating node. The same transaction input and prior state should produce the same output state across the network, which is why determinism matters. Smart contracts can read state, update storage, emit events, and call other contracts.
A Simple Contract Example
pragma solidity ^0.8.20;
contract Counter {
uint256 public value;
function increment() external {
value += 1;
}
}This small example already introduces important ideas: persistent on-chain storage, externally callable functions, and deterministic state transitions.