Etherscan is an Ethereum Block Explorer for Transaction Checks

Etherscan is a public Ethereum search tool and block explorer, meaning it indexes activity from a shared digital ledger. It turns raw blocks, transactions and smart-contract events into searchable pages for checking status, address balances, token transfers, fees and published contract code. Anyone can read those pages without creating an account or connecting a wallet.

Use it like a receipt desk: start with a transaction hash, address, block number, token contract or Ethereum Name Service name. The sections below explain what each page proves, where its numbers come from and when another explorer or your own node fits better.

Bottom line: It is an Ethereum block explorer that indexes public ledger data so users can verify transaction status, address balances, and ERC-20 transfers.

Reading a Transaction Receipt After Sending ETH

Paste the transaction hash into Etherscan when an ETH transfer seems missing from the destination interface. The resulting receipt shows Pending, Success or Failed alongside the sender, recipient, value, nonce, block and gas use. A transaction hash encodes a 32-byte Keccak-256 digest and displays as 64 hexadecimal characters, or 66 with its 0x prefix. That fixed identifier is more precise than searching a ticker or an address with a long history.

A successful status proves that Ethereum executed the transaction and placed its receipt in a block. Confirmations count later blocks built above that block, while finality describes the stronger proof-of-stake checkpoint. A wallet or exchange can wait for its own confirmation threshold before crediting a deposit, so the explorer and the destination interface may update at different moments. The page’s To field identifies the direct recipient; ERC-20 transfers and internal ETH movements appear in separate event or trace views because contracts create them during execution. That separation explains why one hash can contain several visible asset movements.

A new externally owned account starts with nonce 0, then each sent transaction increases it. Matching sender, nonce and chain distinguishes a replacement from an unrelated transfer.

Custodial crediting changes only after the destination service reaches its required confirmation threshold.

Does Etherscan Charge Fees?

Etherscan charges no gas for viewing public pages because a lookup doesn’t alter Ethereum’s state. Browsing a transaction, address or verified contract is free. Read Contract queries use eth_call, which asks a node to simulate a read without recording a transaction. Write Contract changes state, so the connected wallet pays Ethereum gas even though the explorer provides the interface.

A basic ETH transfer between externally owned accounts consumes exactly 21,000 gas units. The receipt reports gas used, effective gas price and transaction fee. One ETH equals 10^18 wei, while 1 gwei equals 10^9 wei, so multiplying gas used by the effective gas price yields the fee in wei. EIP-1559 divides that price into a protocol-set base fee and a priority fee for the block proposer. Unused gas below the chosen limit returns to the sender; the network still charges for computation already performed if execution reverts.

The EIP-1559 base fee can move by at most 12.5% between consecutive blocks. After inclusion, Etherscan displays the observed fee; a pending transaction only has wallet-chosen caps.

How Does Etherscan Turn Blocks Into Searchable Pages?

Where it matters, Etherscan runs infrastructure that indexes Ethereum blocks, receipts, logs and account state into a searchable database. An Ethereum node supplies canonical block and receipt data. The indexer parses logs into token-transfer views, associates contract addresses with verified source and adds labels or ENS names for navigation. Search accepts a block number, 32-byte transaction hash or 20-byte address.

Ethereum divides proof-of-stake time into 12-second slots and 32-slot epochs, making each epoch 6.4 minutes. Each slot is a chance to propose one block, though an empty slot produces no block. Checkpoints occur every epoch, and at least two-thirds of staked ETH must support checkpoint links for finality. Fresh information therefore appears in layers: network broadcast, block inclusion, confirmations, finality and explorer indexing. The public ledger remains the authority when a label or decoded method differs, since names and decoding enrich the interface rather than changing chain state.

Addresses, Token Events and Verified Contract Code

An Etherscan address page combines native ETH activity, token events and deployed contract details for one 20-byte account. EIP-55 keeps the hexadecimal body at 40 characters, while the 0x prefix makes the displayed address 42 characters. Mixed-case checksum letters help software detect some typing errors, but they don’t encode the network.

Address Identity and Token Records

Address pages separate normal transactions, internal operations and token events because each originates through a different EVM mechanism. ERC-20 contracts emit Transfer events for fungible amounts, including transfers of 0 units. Decimals belongs to each token contract; the standard doesn’t force 18, even though many tokens use 18 and USDC uses 6. The explorer scales the raw integer for display. Logs preserve the contract address, indexed topics and emitting block for review.

ERC-20 Balances

An ERC-20 balance comes from the token contract’s balanceOf function, while transfer history comes from emitted events. USDT and USDC rows belong to contract addresses, not ticker text alone. A wallet such as MetaMask may hide a token until its contract is imported, yet the on-chain balance remains under the same account and network.

ERC-721 and ERC-1155 Assets

ERC-721 identifies each non-fungible item with a 256-bit uint256 token ID paired with its contract address. ERC-1155 allows one contract to track multiple fungible or non-fungible token types and emits either TransferSingle or TransferBatch. The metadata image or name can live outside Ethereum, so ownership fields and content availability answer different questions.

Verified Contract Interfaces

Contract pages distinguish bytecode from published source. Etherscan presents 4 verification states: Unverified, Similar Match, Exact Match and Runtime Match. Exact Match compares compiled source plus constructor arguments with the deployment, while narrower matches omit some creation details. Verification makes Solidity or Vyper source and the Application Binary Interface readable; it doesn’t certify business logic or an audit. ABI calldata starts with a 4-byte function selector, followed by arguments encoded in 32-byte words.

Read Contract asks for state without signing. Write Contract submits a signed transaction through a connected wallet, and the outcome changes with payable or restricted contract logic.

Starting With the Right Identifier and Network

A reliable Etherscan lookup starts with the correct network and the most specific identifier you already have. Ethereum Mainnet uses chain ID 1, while Sepolia uses 11155111. The same 20-byte address can have unrelated balances on different EVM networks because an address doesn’t carry chain information.

Decision Checklist for a Lookup

Transaction hash available: open its receipt and match the sender, recipient, amount and network.
Only an address or ENS name available: inspect the address page and choose the relevant activity tab.
Wallet omits a token: select the same network and inspect holdings by token contract address.
Contract behavior matters: check the Contract tab, verification match and ABI before using Read Contract.
Repeated data is required: use API V2 with chainid instead of scraping rendered pages.

Automation changes the entry point, not the underlying evidence. Etherscan API V2 uses one Etherscan key and a chainid parameter for one network per request. Ethereum Mainnet is 1, Base is 8453, Polygon is 137 and Arbitrum One is 42161. Native transactions and ERC-20 transfers use separate account actions, so a complete activity feed must merge both result sets and sort them consistently. Page labels remain useful context, while hashes, addresses, block numbers and log fields stay the durable join keys.

If one hash isn’t found under chain ID 1, the sending wallet’s recorded network decides which explorer instance or API chainid to query.

Blockscout, Otterscan and Direct Node Queries

Blockscout, Otterscan and direct Ethereum node queries offer distinct control, coverage and verification trade-offs beside Etherscan. Blockscout publishes open-source software for EVM chains and supports self-hosted deployments, which fits custom networks or teams that control indexing. Its labels and contract-verification coverage differ by instance. Etherscan operates independently of the Ethereum Foundation, so hosted convenience also concentrates indexing, metadata and availability in one service.

Otterscan is built for local use with an Erigon archive node. It removes the external hosted indexer from the lookup path and exposes optimized ots JSON-RPC methods for address history, internal operations and transaction errors. The trade-off is operational: the user supplies, syncs and maintains the node. Geth’s standard JSON-RPC offers raw blocks, receipts and logs without token pages or curated labels, while Sourcify provides an independent route to verified contract source.

For everyday receipts, Etherscan combines Ethereum data, ENS resolution, token event parsing and verified ABIs in one interface. Those conveniences don’t turn the explorer into a wallet: it never holds private keys, signs transfers or changes balances. A balance visible on-chain belongs to the address on that network, whether MetaMask or another wallet interface lists it. A failed or pending transaction stays governed by Ethereum’s nonce and fee rules. Choose the hosted explorer for speed, Blockscout for open deployment and Otterscan or direct node queries when local control justifies node maintenance.

Wooden letter tiles spelling BLOCKCHAIN on wood

Etherscan: reader questions

Why does Etherscan show tokens that MetaMask doesn’t list?

An on-chain token balance can exist even when MetaMask hasn’t added that token to its visible asset list. Etherscan reads the ERC-20 contract for the selected address and network. Confirm both values, then add the token contract in the wallet if needed. The explorer reports public ledger state; it doesn’t decide which assets a wallet interface renders.

Is an Etherscan account required to check public data?

No account is required to search an address, transaction hash, block, token or verified contract on Etherscan. Public pages remain readable without signing in or connecting a wallet. Registering serves optional site functions such as watch lists, private notes and API-key management; it neither creates an Ethereum address nor grants control over one. Control comes from the private key or smart-account authorization that signs a state-changing transaction. The account remains a website profile.

Does an Etherscan API key work across supported EVM chains?

One Etherscan API V2 key works across supported EVM chains when the request supplies the appropriate chainid. Chain access still follows the API plan, and one request targets one network. Ethereum Mainnet uses 1, Base uses 8453 and Arbitrum One uses 42161. A key created for an older chain-specific explorer isn’t interchangeable with the V2 Etherscan key.

What does an Etherscan public name tag prove?

An Etherscan public name tag is an off-chain label that adds readable context to an address. It doesn’t become part of Ethereum state, prove ownership by itself or replace the 42-character address. Treat the address as the durable identifier and the label as navigation metadata. ENS names differ because Ethereum Name Service records resolve through smart contracts, although the resolved address still decides which account page and balance Etherscan displays.

How are ERC-20 transfers possible when ETH value is zero?

An ERC-20 transfer moves token balances through contract execution, so the transaction’s native ETH value can remain 0. Etherscan decodes the contract call and Transfer event to show the token amount separately. Gas is still paid in ETH by the sender, while the token’s decimals field determines how its raw integer becomes the human-readable amount shown in the interface.

Can Etherscan reverse or recover an Ethereum transaction?

Etherscan can’t reverse, redirect or recover an Ethereum transaction because it indexes the network rather than controlling validators or private keys. A failed transaction reverts its state changes but still consumes gas used during execution. A successful transfer remains governed by Ethereum consensus and the receiving address. If a custodial service controls that address, only that service can decide how and when its internal account ledger credits the deposit under its own account rules.