What is Ethereum? A 2026 guide to smart contracts, ETH, and the L2 ecosystem

Answer first

Ethereum is a decentralized platform for running smart contracts, launched July 30, 2015 by Vitalik Buterin and co-founders. Unlike Bitcoin — which was designed as digital money — Ethereum was designed from the start as a general-purpose programmable blockchain. Anyone can deploy code (smart contracts) that runs autonomously on the network. This design enabled everything that followed: DeFi, stablecoins, NFTs, DAOs, and the modern crypto ecosystem.

Ethereum switched from Proof of Work to Proof of Stake in September 2022 (The Merge) — the largest live protocol change any Layer 1 blockchain has ever completed. Energy use dropped by >99% overnight. The native asset is ETH.

Origin

The Ethereum concept was published in November 2013 by Vitalik Buterin, then a 19-year-old crypto writer who had co-founded Bitcoin Magazine two years earlier. Buterin's insight: Bitcoin's scripting language was intentionally limited (not Turing-complete), which prevented general-purpose applications. What if a blockchain had a full programming language?

Buterin was joined by co-founders Gavin Wood (later Polkadot founder, wrote the technical Yellow Paper), Charles Hoskinson (later Cardano founder), Joseph Lubin (later ConsenSys founder), and several others. The Ethereum Foundation was established as a Swiss non-profit to steward the project.

Mainnet launched July 30, 2015 (Frontier phase). The network has since gone through several planned upgrades:

Homestead (Mar 2016)
DAO fork (Jul 2016 — controversially reversed a hack; created Ethereum Classic split)
Byzantium/Constantinople (2017–2019)
Istanbul/Berlin/London (2020–2021, London introduced EIP-1559)
The Merge (Sep 2022 — PoW to PoS)
Shanghai/Capella (Apr 2023 — enabled staking withdrawals)
Dencun (Mar 2024 — proto-danksharding, cheap L2 data)
Pectra (2025)

How Ethereum works

The Ethereum Virtual Machine (EVM)

The EVM is a global computer running on thousands of nodes simultaneously. Every node runs the same code and produces the same result. Smart contracts are programs deployed to the EVM in bytecode (typically compiled from Solidity or Vyper). Once deployed, a contract is immutable — it runs exactly as coded.

Every operation costs gas — a small ETH fee that compensates validators. Complex operations (heavy storage writes, cryptographic checks) cost more gas than simple ones.

Proof of Stake consensus

Since The Merge (September 2022), Ethereum uses Proof of Stake. Validators:

Stake 32 ETH as economic collateral (solo validator; smaller stakes can join pools)
Propose and attest to blocks in an assigned rotation
Earn ~3–4% APR in staking rewards
Get slashed for provable misbehavior (double-signing, prolonged offline)

Approximately 1 million validators are active as of 2026 — the largest validator set of any Proof of Stake blockchain.

EIP-1559 and the burn

Since August 2021 (London upgrade), every Ethereum transaction has two fee components:

Base fee — algorithmically set by the network based on demand; burned (permanently removed from supply)
Priority fee (tip) — paid to the validator who includes the transaction

When network usage is high, more ETH is burned per block than is issued as staking rewards — making Ethereum net-deflationary. When usage is low, ETH is mildly inflationary. Over 2022–2026, ETH has been roughly neutral to mildly deflationary on net.

Block times and finality

Slot time: 12 seconds (block proposal window)
Epoch: 32 slots (~6.4 minutes)
Finality: two epochs (~13 minutes) — after which reverting the chain would require slashing at least 1/3 of all staked ETH

The Layer 2 ecosystem

Ethereum L1 handles ~15 transactions per second. Its scaling strategy is rollups — Layer 2 chains that execute transactions off-chain and post proofs (or data) back to L1.

Optimistic rollups (assume validity, allow challenge period):

Arbitrum — largest L2 by TVL
Optimism — second-largest
Base — Coinbase's L2, huge consumer growth

Zero-knowledge rollups (cryptographic proofs of validity):

zkSync Era
Starknet
Linea (ConsenSys)
Scroll
Polygon zkEVM

L2s are dramatically cheaper than L1 (typically $0.01–$0.50 per transaction vs L1's $0.50–$20+). Total L2 TPS across the rollup ecosystem exceeds thousands per second. From an ETH value-accrual perspective, L2 usage still consumes ETH for gas (either directly or via posting data to L1).

What's on Ethereum

Stablecoins. USDC, USDT, DAI, and most other regulated stablecoins are natively issued on Ethereum. Combined stablecoin market cap on Ethereum runs in the hundreds of billions.

DeFi. Aave (lending), Uniswap (DEX), MakerDAO/Sky (stablecoin protocol), Curve (stableswaps), Lido (liquid staking), EigenLayer (restaking), and hundreds more. DeFi TVL on Ethereum runs in the tens of billions.

NFTs. OpenSea, Blur, and other marketplaces primarily serve Ethereum NFTs. Bored Ape Yacht Club, CryptoPunks, and most flagship collections live on Ethereum.

RWAs (real-world assets). BlackRock BUIDL, Franklin FOBXX, Ondo Finance products — most tokenized US Treasuries and money-market funds are natively on Ethereum.

Consumer applications. ENS (Ethereum Name Service), Farcaster (via Base), Zora, and various social + payment applications.

ETH tokenomics

Uses:

Gas on Ethereum L1 and most L2s
Staking to earn ~3–4% APR
DeFi collateral across lending, restaking, stablecoin backing
Store of value (spot ETF exposure since July 2024)

Supply:

No hard cap (unlike Bitcoin's 21M)
Post-Merge issuance: ~600,000 ETH/year to validators (down from ~4.9M/year under PoW)
EIP-1559 burn offsets issuance during high usage — often net-deflationary
~120 million ETH circulating in 2026

Staking yield: ~3–4% APR; slightly lower via liquid staking (Lido) after fees.

The Merge — a technical landmark

On September 15, 2022, Ethereum switched from Proof of Work to Proof of Stake in a single upgrade. The change:

Reduced energy use by >99% (from ~78 TWh/year to <0.01 TWh/year)
Reduced ETH issuance by ~90% (from ~4.9M/year to ~600K/year)
Eliminated mining and the associated hardware market
Introduced slashing as a new security mechanism

The Merge was executed live on mainnet with tens of billions of dollars secured on the network. No other Layer 1 has completed a comparable protocol swap.

Where Ethereum sits in 2026

Market position. ETH is the second-largest cryptocurrency by market capitalization after Bitcoin. Spot Ethereum ETFs launched in the US in July 2024, opening institutional access.

Ecosystem depth. By virtually every measure of blockchain ecosystem depth — DeFi TVL, stablecoin market cap, developer count, NFT trading volume — Ethereum is the largest.

Competitive position. Ethereum's main competitors are Solana (throughput-first), and increasingly Monad (EVM-compatible high throughput). Ethereum's edge is depth of ecosystem and security; competitors' edge is throughput and lower fees.

How to buy Ethereum — practical guide
What is Ethereum gas? — fee mechanics
Best Ethereum Layer 2s — L2 comparison
What is Bitcoin? — the design contrast
What is Solana? — throughput-focused alternative
What is DeFi? — the applications Ethereum hosts