What Is Ethereum? Smart Contracts, Gas Fees, and the EVM Explained

Ethereum is a decentralized, open-source blockchain platform launched in 2015 by Vitalik Buterin and a team of co-founders. While Bitcoin was designed primarily as a digital currency, Ethereum was built to be a general-purpose platform for decentralized applications (dApps) through the use of smart contracts.

A smart contract is a self-executing program stored on the Ethereum blockchain. When predefined conditions are met, the contract automatically executes the agreed-upon actions. This eliminates the need for intermediaries in many types of transactions, from simple token transfers to complex financial instruments.

The Ethereum Virtual Machine (EVM) is the runtime environment for smart contracts on Ethereum. It is a global, decentralized computer that executes code exactly as programmed across thousands of nodes simultaneously. The EVM ensures that every node reaches the same result, maintaining consensus across the network.

Gas fees are the transaction costs on Ethereum, paid in ETH (Ether, Ethereum's native currency). Every operation on the EVM requires a certain amount of 'gas,' and users pay for this gas to compensate validators for processing their transactions. Gas prices fluctuate based on network demand, which means transactions can become expensive during periods of high activity.

In September 2022, Ethereum transitioned from Proof of Work to Proof of Stake through an upgrade known as 'The Merge.' Under Proof of Stake, validators stake ETH as collateral to participate in block validation, replacing the energy-intensive mining process. This reduced Ethereum's energy consumption by approximately 99.95%.

Ethereum's ecosystem includes decentralized finance (DeFi) protocols, non-fungible tokens (NFTs), decentralized autonomous organizations (DAOs), Layer 2 scaling solutions, and thousands of tokens built on the ERC-20 standard. This rich ecosystem has made Ethereum the foundation for much of the innovation in the blockchain space, though it faces ongoing competition from other smart contract platforms.