How do you check a crypto wallet on a block explorer?

What an address is

An Ethereum address is a 42-character string of hexadecimal characters that starts with "0x".² Wallets controlled by a private key and smart contracts both have addresses in this same format.²

They look the same, but explorers present them differently.² A contract's page shows extra things, such as its code and who created it (lesson 5).⁵

The top of the page

• Balance: how much ETH the address holds now, and roughly what it is worth.¹
• Token holdings: the tokens it holds, with a total dollar value where the explorer has prices.¹
• Funded by: the first address and transaction that sent it ETH.²
• Multichain: other chains where the same address appears.¹

The history tabs

So if someone sends you tokens, look in the token transfers tab, not the main one. Etherscan says that is where token transactions are listed.⁶

Explorers can lag. Etherscan says a token can show in the transfers tab before it shows in the balance, because the balance can be slow to refresh.⁶

Labels are the explorer's opinion

Explorers add names to make addresses easier to read. Etherscan says it collects public data not just from the blockchain but also from the internet.³

• Public name tags say who owns an address, or what a contract is for.³
• Labels put an address in a category, such as an exchange.³
• Solscan also labels Solana wallets by behaviour, such as how many NFTs they trade.⁷

None of this is on the chain. A transaction itself names its sender and receiver only by address.^8,9 Etherscan says it only tags a person's address when that person has said publicly that it is theirs.³ It also admits a tag can turn out to be false, for example when someone was falsely claiming an address.³

ethereum.org's scam-token guide notes that Etherscan is not an authoritative source of truth about which tokens are legitimate, because a decentralised network can't have one. It adds that tokens Etherscan flags as scams are likely to be scams.⁴ Treat a label as a clue, not as proof.^4,3

Lookalike addresses

Attackers make addresses that start and end with the same characters as one you use. Shortened in the middle, the two look exactly the same.¹⁰

They then put fake entries in your history. One trick, Etherscan explains, is to create a fake token and make it show a transfer from the lookalike address, with the same amount as a real transfer you just received.¹⁰ The hope is that next time you copy the wrong address from your history.¹⁰

Etherscan's advice includes using a contact list for addresses you pay often, and comparing a suspicious transaction with several other sources.¹⁰ It also hides transfers of tokens with a poor reputation by default.¹⁰ Module 10 covers this attack in more detail.¹⁰

Approvals

Some explorers show which apps an address has allowed to spend its tokens, and let you revoke those approvals.^1,11 ethereum.org says these permissions never expire, and revoking one is a transaction that costs a fee.¹¹ Module 12 explains approvals.⁹

Checking with a second source

An explorer is one company's copy of the chain. Etherscan itself offers a tool, EthValidate, to check balances and transaction statuses against other nodes.¹² For anything important, looking at a second explorer is a cheap extra check.¹⁰