Block Explorer

A block explorer is a website or tool that lets anyone browse a blockchain's contents — transactions, addresses, blocks, and balances — much like a search engine for the ledger. Because public blockchains are open data, explorers simply index that data and present it in a readable form: paste in a transaction ID and you see its amount, fee, and confirmation status; paste in an address and you see its balance and full history.

Well-known examples include Etherscan for Ethereum and mempool.space or Blockstream Explorer for Bitcoin; most other chains have their own equivalents, such as Solscan for Solana. For example, if a friend says they sent you bitcoin but your wallet shows nothing, you can paste your address into an explorer and immediately see whether a transaction to it exists, whether it is still unconfirmed, and what fee it paid — settling the question without trusting anyone's word.

A common misconception is that you need an account or permission to look up blockchain activity; explorers are free and open, which is precisely the point — the transparency of public blockchains means anyone can audit any transaction ever made. Explorers also serve advanced uses: reading smart-contract code, tracking token transfers, watching large "whale" movements, and verifying that a token's contract address is the genuine one. The one thing an explorer cannot show is who owns an address, since blockchains record addresses, not identities.