Ethereum

Ethereum is a decentralized, open-source blockchain platform that launched in 2015 following a proposal by Vitalik Buterin and a group of co-founders. Rather than functioning only as a payment network, Ethereum was built as a programmable "world computer": a global network of nodes that all execute the same code and agree on the same state, so that applications running on it cannot be shut down, censored, or altered by a single party.

The core innovation is the smart contract, self-executing code deployed on-chain that runs exactly as written once triggered, without needing a trusted intermediary. Developers write these contracts mainly in Solidity, and every operation they perform consumes "gas," a fee paid in Ether that compensates the network for computation and storage. This model has powered thousands of applications, from decentralized exchanges and lending markets to NFT collections and DAOs.

In September 2022, Ethereum completed "The Merge," switching its consensus mechanism from energy-intensive mining to proof of stake, where validators lock up Ether to propose and confirm blocks. Roughly 30 percent of all Ether is now staked this way. Because base-layer capacity is limited, most everyday activity has shifted to Layer 2 rollups that bundle transactions off-chain and settle proofs back to Ethereum, keeping fees lower while inheriting its security. Risks include smart-contract bugs, high fee spikes during congestion, and the ongoing complexity of coordinating upgrades across a large validator set.