How to Use Etherscan: Reading Ethereum Transactions in 15 Minutes

What Etherscan is#

Etherscan launched in 2015 as a frontend for Ethereum's blockchain — letting humans browse the public ledger without running a node. Today it indexes every block, transaction, contract, and event on Ethereum mainnet, plus several testnets. Sister sites cover other EVM chains:

Chain	Explorer
Ethereum	etherscan.io
BNB Smart Chain	bscscan.com
Polygon	polygonscan.com
Arbitrum	arbiscan.io
Optimism	optimistic.etherscan.io
Base	basescan.org
Avalanche	snowtrace.io

Same interface, different chains. All block explorers are free to use. They don't custody anything — they only read on-chain data.

Look up a transaction#

Most common use case: your swap got stuck and you want to know why.

1. Copy the transaction hash from your wallet (MetaMask → Activity → click pending → "View on Etherscan"). It looks like 0xabc123....
2. Paste into Etherscan's search bar at etherscan.io.
3. Read the top section: Status (Success / Pending / Failed), Block number, Timestamp, From/To addresses, Value (ETH sent), Transaction Fee (gas paid).
4. If Status is Failed, click "Click to see More." Etherscan shows the revert reason — common ones: insufficient allowance, slippage too low, pool empty, contract paused.
5. If Status is Pending for more than 10 minutes, your gas fee was too low. Speed up by submitting a replacement transaction with higher gas (MetaMask → Activity → Speed up).

Look up a wallet address#

Paste any Ethereum address into the search bar. The wallet page shows:

• Current ETH balance
• Total transaction count
• Current ERC-20 token holdings
• NFT holdings
• Full transaction history (with tabs for Transactions / Internal / ERC-20 / NFT)

Use cases: confirm your own activity, check a counterparty's history before sending them funds, investigate a suspicious wallet that received funds you didn't recognize.

Pro tip: the "Etherscan label" tag shows known wallet identities (Vitalik's main wallet, exchange hot wallets, known scammers).

Token Approval Checker — the most important Etherscan feature#

Every time you click "Approve" on a DApp (Uniswap, OpenSea, any DeFi protocol), you grant that contract permission to spend a specific token from your wallet. These approvals are persistent — they don't expire. Old approvals from compromised or malicious sites are the #1 cause of wallet drainage in 2026.

Etherscan's Token Approval Checker at etherscan.io/tokenapprovalchecker shows and revokes all approvals on your wallet.

1. Go to the link above.
2. Paste your wallet address (no need to connect — read-only).
3. Etherscan lists all active approvals. Sort by "Allowance" descending — "Unlimited" approvals are highest risk.
4. For each approval, decide: do you still use this contract? Old approvals from "free NFT mint" or "connect to claim airdrop" should be revoked.
5. Click "Revoke" next to risky approvals. Connect MetaMask, pay ~$2–5 in gas per revoke. Worth it.
6. Alternative: revoke.cash and rabby.io have cleaner interfaces for the same task. Whichever you use, do this quarterly.

See Wallet drainer explained for why this matters.

Verify a smart contract#

Before buying a new token, you should verify the contract's identity. Two checks:

1. The contract's source code is published and matches what's deployed.
2. The contract behavior matches what the project claims.

On a token's contract page (e.g. etherscan.io/token/0x...), look for the Contract tab. A green checkmark with "Verified" means the source code is published. Click to read the actual Solidity code.

Most beginners can't audit code line-by-line, but the existence of verified code is itself a positive signal. Unverified contracts (compiled binary only, no source) are higher risk — pair them with a GoPlus scan before going anywhere near them.

Gas tracker — when to buy and sell#

Gas fees on Ethereum fluctuate wildly with network demand. Etherscan's Gas Tracker (etherscan.io/gastracker) shows current gas in Gwei plus historical trends:

• Low gas (under 20 Gwei) — transactions cost $1–3.
• High gas (over 100 Gwei) — transactions cost $20–50+.

For non-urgent transactions, check first. Patterns: gas is usually lower on weekends and overnight US-time. New NFT drops or token launches spike gas — wait if you can.

Non-EVM block explorers#

Solana, Bitcoin, and other non-EVM chains use different explorers but the concept is the same:

• Solana — solscan.io, solana.fm
• Bitcoin — mempool.space, Blockstream Explorer
• Tron — tronscan.org

The "paste hash to see transaction" workflow is universal across chains.

Bottom line#

Etherscan is the closest crypto has to a public records office. You don't need to read code to get value from it — being able to debug a stuck transaction, audit your own approvals, and verify a contract exists takes maybe an hour to learn and prevents most of the boring categories of loss. Bookmark it, get comfortable, and run the approval check every quarter on every wallet you use.

Next reads: Wallet drainer explained · GoPlus token security · How to keep crypto safe.