What’s In A Block, Anyway? | An Introduction to Block Explorers
This article originally posted at www.coincentral.com
A blockchain, as a purveyor of this site you already likely know, is an immutable, distributed database; each new “block” of data is confirmed to be truthful by some method (usually a Proof of Something) by a majority or measured minority. Almost all blockchain blocks contain primarily a batch of transactions that represent an exchange of that chains associated cryptocurrency. For example, the latest block committed to the Ethereum blockchain, contains a rich plethora of data within the block such as the block height, the number of transactions confirmed within the block, transaction hashes for all the transactions confirmed, the total value of ether exchanged within the block, the total value of gas & fees within the block & the reward for mining the block.
In short, there’s a trove of beautiful blockchain data that naturally exists within each blockchain project. Ask almost any enthusiast for a price tracker or mock portfolio & you’ll find yourself in a deluge of .io’s & .co’s; but ask any crypto enthusiast where they can find all the newest transactions confirmed in the latest Bitcoin block, and you’re sure to receive a blank stare.
To be fair, understanding this data is hard, seeking it out and understanding it, is well, even harder. Thankfully, a new class of websites & apps are breaking into the crypto scene that make exploring blockchain significantly more intuitive.
Enter Block Explorers
A blockchain explorer is simply a web or mobile app as we know it that directly interfaces with the data contained on a blockchain. That’s it in a nutshell. In fact, you’ve probably stumbled your way into one of the popular block explorers while surfing the crypto-web without really understand the depth of the tools at your disposal:
We’ll go through an Etherscan example later at length; for the most part, these block explorers have common core features with very similar interfaces.
Block Explorers Common Features
A Block Explorer is basically a search platform that allows users to easily lookup blocks, transactions, smart contracts, and pretty much every data point in between for a specific blockchain.
Almost every blockchain explorer will have a constantly updating feed of blocks for their main page. The Blockchain.info & Etherscan.io websites have a stream of the latest Bitcoin & Ethereum blocks published, respectively, on their individual chains. I’ve highlighted both interfaces below in red:
The most basic feature of a cryptocurrency block explorer is that it shows the latest blocks in the blockchain per the images above. Each row represents a block & without clicking in, we can already see a substantial amount of detailed information about each specific block. The Blockchain.info BTC & Etherscan ETH block explorers both offer the following data from this row representation:
- Block Height – the order number of this specific block (remember, a blockchain starts with an origin block, block 0)
- Block Age – the amount of time that has passed since the specific block was published to the blockchain
- # of Transactions – the number of confirmed transactions that are now part of a blockchain’s history
- Relayed By / Mined By – the name of the mining pool or entity that published said last block to the blockchain
All block explorers should list new blocks the second they’re generated in their respective chains. As you can see, we’re already diving a bit deeper into the raw data outputted by cryptocurrency blockchains; but this is only the beginning, clicking on a row (block) on either Blockchain.info or Etherscan.io reveal substantially more data about that block.
Clicking on a specific network block reveals significantly more data. Again, below we use our two favorites block explorers assuming the user has now clicked on a block preview from the landing page:
Both screenshots above show the actual data stored within each block in the Bitcoin & Ethereum blockchain respectively. First, you’ll find that all of the data points that we saw in the previous views show up here as well, including height, & age.
However, we also find significantly more data than available to us before. We’re now getting into the neck of the woods in terms of raw blockchain data. Some of the more fascinating additional points seen above are:
- Hash: the unique identifier that’s a result of a confirmation algorithm such as SHA256 & a previous block hash
- Transaction Fee / Gas Used: the total amount of transactions fees in a Bitcoin block or gas in an Ethereum block
- Transaction Hashes: the unique identifier for each individual transaction that was confirmed within each block
We’re now deep under the hood of the blockchain world by reading the raw data contained within each block. As you’ve probably deduced, since block explorers provide us with individual transactions hashes, they also allow us to explore these individual transactions at a deeper length.
Depending on which block explorer one uses, there are some additional features to be enjoyed as well. Blockchain.info, for example, has become much more than just a block explorer, as it also provides statistics and charts pertaining to the bitcoin network.
Even though the name “block explorer” would suggest it can only be used to look up individual network blocks, that is not the case. Block explorers can also search for transaction IDs and wallet addresses, making them quite a nifty tool to check on specific transactions to your own wallet address. A block explorer quickly becomes a tool everyone in the cryptocurrency relies on virtually every day, yet they are far more versatile than people anticipate.