Block explorer is an online blockchain webpage that allows users to search for information on the blockchain such as transaction, balances etc. They allow users to view and query individual blocks thus providing visibility to any one of the transactions or other actions.
Block explorers are a key part of cryptocurrency’s mission of transparency and decentralization, and the universal visibility of all transaction data is one of the key differentiation between cryptocurrency and conventional currencies.
There is a wide range of block explorers available online, with the most popular including Blockchain.com, Mempool, Bitaps, Blockstream, Multihash, Blockchain Info, and Bitupper Explorer.