Block Explorer

In simple terms

A block explorer is a search engine for a blockchain. Paste in a transaction ID or an address and it shows the status, the amount, the fee and the history, without needing an account.

Definition

A public website for searching a blockchain — looking up transactions, addresses, blocks and contracts.

In depth

A block explorer runs a full node, indexes the chain into a queryable database, and exposes it over a web interface and an API. Beyond lookups, explorers commonly surface decoded contract calls, token transfers derived from event logs, verified source code for deployed contracts, and aggregate network statistics such as fees and pending transaction counts. The data is a rendering of public chain state, so two reputable explorers should agree, and any discrepancy is an indexing lag rather than a difference in the underlying ledger.

How does Block Explorer work?

You paste a transaction hash, address, or block number into the search field. The explorer looks it up in its index and renders it: for a transaction, the status, block, confirmations, sender, recipient, amount and fee; for an address, the balance and full transaction history; for a contract, the code and recent interactions. Because the chain is public, none of this requires permission, and the explorer is a viewer rather than an authority.

An example

A withdrawal has not appeared after twenty minutes. Pasting the transaction hash into an explorer shows it as pending with an illustrative fee well below the current average, which explains the delay: it is queued rather than lost, and it will confirm when demand falls or be dropped and returned to the sender's available balance.

Figures are illustrative only.

What beginners get wrong

• Panicking before checking. Most "missing" transfers are visible on an explorer as pending or already confirmed, and the delay is at the receiving service.
• Using an explorer for the wrong chain. Each chain has its own, and a valid hash simply will not be found on the wrong one.
• Trusting a token page as proof of legitimacy. Anyone can deploy a token and have it appear on an explorer, and appearing there is not an endorsement.
• Reaching an explorer through a search advertisement. Phishing clones exist; type or bookmark the address instead.

Related terms

• Transaction
• Wallet Address
• Confirmation
• Block
• On-Chain Analysis
• Mempool

Part of

How does a blockchain transaction actually work? — the subject page for blockchain mechanics, with all 15 of its definitions in one place.