A block explorer is an online platform that allows you to navigate through the blockchain, searching for various things including addresses, blocks, transactions, and so on. For example, if you visit https://www.blockchain.com/explorer, you can see a block explorer utility for the Bitcoin and Ethereum blockchains, as follows:
Inside of this block explorer, you can search the entire blockchain for a specific block, hash, or transaction, or any other piece of data that is required. The utility also displays results on an interface that's easy to understand. For example, if we search for Block #549897 in the block explorer, you'll see all the details of that particular block, as seen in the following screenshot:
This is exactly what we're going to build for our blockchain in this chapter.