Ethereum (ETH)

Ethereum launched in 2015, conceived by Vitalik Buterin as the first blockchain with programmable smart contracts. The Ethereum Virtual Machine (EVM) became the de facto standard for decentralized applications, and the overwhelming majority of DeFi protocols, NFT marketplaces, and token standards originated on Ethereum. USDT (Tether) was first issued as an ERC-20 token on Ethereum, and the network still holds the largest share of USDT liquidity in DeFi.

In September 2022, Ethereum completed "The Merge" — a transition from energy-intensive Proof of Work to Proof of Stake consensus. This reduced the network's energy consumption by over 99% and changed how blocks are produced. However, gas fees remained a challenge: Ethereum's fee market is auction-based, meaning costs spike during periods of high demand. A standard ERC-20 USDT transfer can cost anywhere from $0.50 during quiet periods to $50 or more during network congestion.

To address the fee problem, the Ethereum ecosystem has embraced Layer 2 (L2) scaling solutions such as Arbitrum, Optimism, and Base. These rollups process transactions off the main chain and batch-post proofs back to Ethereum, dramatically reducing costs while inheriting the security of the base layer. For users who need the cheapest USDT transfer, bridging to an L2 is often the best strategy.

Despite its higher fees, Ethereum remains the gold standard for DeFi, holding the largest Total Value Locked (TVL) of any blockchain. Its developer ecosystem, tooling, and security track record are unmatched, making it the foundation on which much of the crypto economy is built.