Block Explorer

A block explorer is a web interface for browsing the Bitcoin chain. Type in an address, transaction ID, or block height; get back the on-chain data associated with it: balances, transaction history, confirmations, fees, mempool status.

Block explorers are universally useful and universally a privacy compromise. Every search you make tells the operator which addresses or transactions you care about. For casual lookups this is fine; for queries related to your own wallet it's a privacy leak that gets correlated with your IP, your browser fingerprint, and any cookies in play.

Two explorers worth knowing:

• mempool.space - open-source, built around the fee market, and designed to be self-hosted against your own node.
• ChainQuery.com - the Bitcoin explorer this site is paired with. Fed by its own full node rather than a third-party API; cookieless analytics, no fingerprinting, no cross-site tracking.

For privacy-sensitive use cases, run your own node and use a local explorer (a self-hosted mempool instance or BTC RPC Explorer, both of which read from your own Bitcoin Core node). A full node plus a local explorer means you see the chain data and only you - no third party logs your queries.

For everyday "did my transaction confirm" or "what's the current fee market" type questions, public explorers are fine. Just don't paste your savings address into a search box on every site you visit.