Imagine trying to understand a city by peering through a keyhole. You might catch glimpses — cars driving by, people on the street — but the full system of roads, buildings, and interactions remains hidden. For many, this is what blockchain feels like.
A blockchain explorer is a tool to make blockchain activity more legible and more tangible. An explorer makes the activity on a blockchain network visible, traceable, and understandable, turning cryptic block data into readable information.
Whether you’re an investor, developer, auditor, or simply curious, a blockchain explorer provides a clear view of what’s actually happening onchain.
This is post is part of an ongoing series that we call Nexus 101. You might also be interested in our post about how to use the Nexus CLI:
At its core, a blockchain explorer is a search engine and analytics dashboard for a blockchain. Just as you might search Google to find websites or data across the Internet, you use a blockchain explorer to look up transactions, addresses, blocks, contracts, and tokens on a blockchain.
But it’s more than a search bar. Explorers decode and present raw blockchain data — data that’s stored in cryptographic formats across distributed nodes — in a way that humans can interpret. They help you answer questions like:
Has my transaction been confirmed?
How much gas (or transaction fees) did that contract execution consume?
How many tokens does this address hold?
What’s trending in terms of onchain activity?
Explorers democratize access to blockchain data. Not only can you study and vet your own transaction data, but you can also look at other onchain activities and movements. Explorers create a sense of openness and fairness. They replace the need for blind trust in companies, institutions, or organizations with facts that are verifiable onchain.
Blockchains, by design, are public and append-only, meaning new data can be added but existing data can't be deleted. Every transaction, contract deployment, or token transfer is recorded in blocks. These blocks are broadcast to the network, validated by nodes, and permanently stored in a chain-like data structure.
Blockchain explorers run full nodes of the networks they track. These nodes receive the same data as any participant in the network. The explorer software continuously parses this raw block and transaction data, indexes it, and exposes it through user-friendly interfaces — both graphical dashboards and APIs.
A well-built explorer typically consists of:
A data ingestion layer, connected to the blockchain via RPC (remote procedure call) or direct node integration.
An indexing engine that parses and structures blockchain data into categories like transactions, addresses, tokens, and contracts.
A frontend interface where users can search and browse.
An API layer often used by developers to programmatically access onchain data.
Together, these layers turn a blockchain’s constant stream of cryptographic information into an elegant, browsable ledger of activity.
Another way to interact onchain is through a blockchain-based wallet. Check out our wallet guide for more info.
Blockchain technology promises transparency, but it doesn’t guarantee readability. Explorers close that gap. They enable everything from basic use to institutional-grade analysis.
Here are some common use cases:
Everyday users can verify whether a payment went through or how long a transaction is taking.
Developers monitor smart contract deployments, test execution outcomes, and debug live interactions.
Traders and analysts scan for whale movements, token velocity, or unusual activity.
Auditors and regulators examine provenance and patterns in onchain history.
Builders use explorer APIs to integrate on-chain data into their apps and dashboards.
In short: if the blockchain is the infrastructure, the explorer is the interface. Without it, trustless transparency would remain hidden in plain sight.
An example of publicly available transaction information on the Nexus blockchain explorer.
Part II: Decoding the Metrics
Understanding how a blockchain functions requires more than just looking at blocks. The real insight comes from understanding what the data tells us. Let’s break down five core explorer metrics and what they reveal.
Transactions
Definition: A transaction is any action recorded on the blockchain. This includes sending funds, deploying a smart contract, calling a contract method, or minting a token.
What it shows: The volume and nature of transactions indicate the activity level on a network. Explorers show you when transactions occurred, their status (pending, confirmed, failed), associated fees, and involved addresses.
Why It matters: High transaction volume can signal growing usage or network congestion. For developers and users, transaction histories provide audit trails, proving that something happened — and when.
Deeper insight:
Failed transactions often include error messages and consumed gas data.
Pending transactions show activity details — useful for estimating congestion or other issues that might affect transaction completion.
Time-to-finality can be inferred by comparing timestamps across blocks.
An example of transaction details available on the Nexus blockchain explorer.
Total contracts
Definition: Smart contracts are self-executing pieces of code deployed onchain. Total contracts refers to the cumulative number of contract deployments.
What it shows: This metric indicates the level of developer engagement and composability. Each contract represents a deployed app, tool, or service — DeFi protocols, DAOs, NFTs, games, and more.
Why it matters: A growing number of contracts suggests innovation and builder activity. Looking deeper, explorer pages often show which contracts are most called, verified, or forked.
Deeper insight:
Verified contracts (those with readable source code) increase transparency.
Contract interaction charts show what kinds of onchain activity are popular —and what’s not.
By analyzing contract creation over time, you can spot ecosystem growth spurts.
An example of the Testnet III dashboard in the Nexus blockchain explorer.
Transaction fees
Definition: Fees, also called gas, are paid by users to include their transactions in a block. The fee incentivizes validators to process the transaction.
What it shows: Explorers display fee amounts in native tokens, fee breakdowns (base fee, priority tip), and historical fee charts.
Why it matters: Fees reflect demand. High gas costs usually signal network congestion or high-value competition for block space. They also reveal economic incentives and user friction.
Deeper insight:
Fee spikes often correlate with popular NFT mints, airdrops, or market volatility.
Explorers with fee estimator tools help users avoid overpaying on transactions.
Aggregated fee metrics can indicate which apps are driving network demand.
Definition: Addresses are public identifiers on the blockchain, similar to account numbers. Total addresses is the count of all unique addresses that have appeared on-chain.
What it shows: Growth in address count suggests increasing adoption. But it’s worth noting that one individual can generate many addresses.
Why it matters: While not a perfect proxy for users, total addresses offer a directional signal. A sharp uptick often follows viral events or ecosystem launches.
Deeper insight:
Active addresses (those that send/receive) are more meaningful than total count.
Address clustering and behavior patterns can be analyzed to estimate real users.
Comparing address growth across chains helps benchmark ecosystem maturity.
Blockchain explorers are tools that make the infrastructure for a transparent internet accessible. As more of our digital lives move onchain, from payments to credentials to media, explorers will become essential interfaces to inspect and verify what actually happened.
At Nexus, we believe that verifiability is the next frontier of the Internet. Explorers are another layer in that future: Letting everyone — not just experts — look under the hood and see for themselves.
Daniel McGlynn
Daniel McGlynn
