Ethereum, Start Here

Updated 2026-10-29

Short answer: Ethereum is a blockchain that runs programs ("smart contracts"), which is why most tokens, DeFi apps and NFTs live on it or on networks built around it. You pay fees ("gas") in ETH. Your 0x address is the same on Ethereum and on its layer 2 networks such as Base, Arbitrum and Optimism, and on other EVM chains like BNB Chain, Polygon, Avalanche and Flare.

Gas fees

• Every transaction costs gas, paid in ETH, even if you're sending a token.
• Fees on Ethereum itself can be a few dollars or more when it's busy. Layer 2 networks (Base, Arbitrum, Optimism) are much cheaper and still use ETH for fees.
• Keep a little ETH on each network you use, or you can't move your tokens there.

Tokens and approvals

• Tokens follow a standard called ERC-20. Anyone can create one with any name, so fake "USDC" or "free reward" tokens are common. Check the contract address on the project's own site.
• Apps ask you to approve them to spend a token. Old or unlimited approvals are how many wallets get drained. See how to check and revoke token approvals.
• Read what you sign: how to read a transaction before you sign.

Staking

You can stake ETH to earn a yield, directly, through an exchange, or with liquid staking tokens like stETH or rETH. See staking on Ethereum and Solana.

Watch out

• Sending on the wrong network. ETH on Base and ETH on Ethereum are separate. Check the network your exchange or wallet uses.
• Fake airdrops and claim sites that ask you to approve or sign. Real claims don't need an approval.

On Crypto Lighthouse

• [Portfolio](/portfolio): your tokens on Ethereum and its layer 2s, DeFi positions, recent activity and liquid staking yields.
• [Approvals](/rewards): check and revoke risky approvals on Ethereum, Base, Arbitrum, Optimism and more.
• [Check an Address](/check) and token checks for scam signs.

Learn more at ethereum.org.