vocabulary: name: Arbiscan Vocabulary description: >- Domain vocabulary for the Arbiscan blockchain explorer and API platform, covering Arbitrum One Layer 2 blockchain concepts, transaction types, token standards, smart contract data, and Etherscan V2 API terminology used when querying Arbitrum One data. version: '1.0' created: '2026-06-13' modified: '2026-06-13' blockchain-concepts: - term: Arbitrum One definition: >- The primary Arbitrum Layer 2 (L2) network, an Ethereum-compatible optimistic rollup chain (chain ID 42161) that executes transactions off-chain and posts compressed proofs to Ethereum mainnet, providing lower fees and higher throughput while inheriting Ethereum security. aliases: - ARB One - Arbitrum L2 related: - Optimistic Rollup - Layer 2 - Ethereum - term: Optimistic Rollup definition: >- A Layer 2 scaling technique that assumes transactions are valid by default and only runs computation (fraud proofs) when a dispute is raised during a challenge window. Arbitrum One uses this approach to batch and settle transactions on Ethereum mainnet. related: - Arbitrum One - Layer 2 - Fraud Proof - term: Layer 2 definition: >- A secondary blockchain framework or protocol built on top of an existing Layer 1 blockchain (such as Ethereum) to improve its scalability, throughput, and transaction cost. Arbitrum One is a leading Ethereum Layer 2 network. aliases: - L2 related: - Arbitrum One - Optimistic Rollup - Ethereum - term: EVM definition: >- Ethereum Virtual Machine — the sandboxed runtime environment that executes smart contract bytecode. Arbitrum One is EVM-compatible, meaning Ethereum smart contracts and tools work with little or no modification on Arbitrum. related: - Smart Contract - Arbitrum One - Solidity - term: Block definition: >- A unit of data on the Arbitrum One chain containing a batch of ordered transactions, a reference to the parent block hash, a miner/sequencer address, and block metadata such as gas used, gas limit, timestamp, and difficulty. Blocks are identified by block number and block hash. related: - Transaction - Block Reward - Sequencer - term: Transaction definition: >- A cryptographically signed instruction from an Arbitrum One account that either transfers ETH, interacts with a smart contract, or deploys a new contract. Transactions are identified by their transaction hash and are permanently recorded on-chain once included in a block. related: - Block - Gas - Internal Transaction - term: Internal Transaction definition: >- A value transfer or contract call that occurs as a result of smart contract execution, not originating directly from a user-signed transaction. Internal transactions do not appear on-chain individually but are tracked by Arbiscan via execution trace analysis. related: - Transaction - Smart Contract - Trace - term: Gas definition: >- The unit measuring computational effort required to execute a transaction or smart contract operation on Arbitrum One. Gas fees are paid in ETH (the native token) and are significantly lower on Arbitrum One than on Ethereum mainnet due to L2 batching. related: - Gas Price - Gas Limit - Transaction - term: Gas Price definition: >- The amount of ETH (in Gwei) a user is willing to pay per unit of gas consumed by a transaction. On Arbitrum One, gas prices are determined by the sequencer and fluctuate with network demand, typically ranging from 0.01 to 0.1 Gwei under normal conditions. related: - Gas - Gwei - Transaction - term: Gwei definition: >- A denomination of ETH equal to 10^-9 ETH (one billionth of an ether), commonly used to express gas prices. On Arbitrum One, gas prices are often measured in fractions of a Gwei due to the low-cost L2 environment. related: - Gas Price - Wei - ETH - term: Wei definition: >- The smallest denomination of ETH, equal to 10^-18 ETH. All ETH balances and value transfers in the Arbiscan API are expressed in wei to avoid floating-point precision issues. related: - Gwei - ETH - Transaction smart-contracts: - term: Smart Contract definition: >- Self-executing code deployed at a specific address on Arbitrum One that enforces agreement terms when predefined conditions are met. Smart contracts on Arbitrum One are written in EVM-compatible languages such as Solidity or Vyper, and their source code can be verified and published via Arbiscan. related: - ABI - Solidity - Contract Verification - term: ABI definition: >- Application Binary Interface — the JSON description of a smart contract's public interface, specifying function names, input/output parameter types, and event signatures. The ABI is required to call contract functions programmatically and is available via the Arbiscan API for verified contracts. related: - Smart Contract - Contract Verification - Function Selector - term: Contract Verification definition: >- The process of submitting a smart contract's source code to Arbiscan for compilation and comparison with the deployed on-chain bytecode. Verified contracts allow users and developers to inspect source code, interact with functions directly, and confirm contract behavior. related: - Smart Contract - ABI - Source Code - term: Proxy Contract definition: >- A smart contract design pattern where one contract (the proxy) delegates calls to a separate implementation contract, enabling contract logic to be upgraded without changing the contract address. Arbiscan identifies proxy contracts and links to their current implementation. related: - Smart Contract - Implementation Contract - Upgradeable Contract - term: Solidity definition: >- The most widely used high-level programming language for writing Ethereum and Arbitrum One smart contracts. Solidity code is compiled to EVM bytecode before deployment, and verified source code is retrievable via the Arbiscan contract API. related: - Smart Contract - EVM - Contract Verification token-standards: - term: ERC-20 definition: >- The fungible token standard on Ethereum and EVM-compatible chains like Arbitrum One, defining a common interface including transfer, approve, allowance, and balance functions. Major ERC-20 tokens on Arbitrum One include USDC, USDT, ARB, WBTC, and wrapped ETH (WETH). related: - ERC-721 - ERC-1155 - Token Transfer - term: ERC-721 definition: >- The non-fungible token (NFT) standard on Ethereum and EVM-compatible chains, where each token has a unique ID and represents a distinct digital asset. Arbiscan tracks ERC-721 transfers and inventory per address. aliases: - NFT related: - ERC-20 - ERC-1155 - Token Transfer - term: ERC-1155 definition: >- A multi-token standard supporting both fungible and non-fungible tokens within a single contract. ERC-1155 is commonly used for gaming assets and collections. Arbiscan tracks ERC-1155 transfers and balances per address. related: - ERC-20 - ERC-721 - Token Transfer - term: Token Transfer definition: >- An on-chain movement of ERC-20, ERC-721, or ERC-1155 tokens from one address to another, emitted as a Transfer event in the token contract. Arbiscan indexes token transfers and makes them queryable by address, contract, or block range. related: - ERC-20 - ERC-721 - Event Log explorer-concepts: - term: Chain ID definition: >- A unique numeric identifier for a blockchain network used in the Etherscan V2 API to specify the target chain. Arbitrum One uses chain ID 42161. Other Arbitrum networks include Arbitrum Nova (42170) and Arbitrum Sepolia testnet (421614). related: - Arbitrum One - Etherscan V2 - API Key - term: Etherscan V2 definition: >- The unified Etherscan API platform that provides a single API key and endpoint for querying blockchain data across 60+ EVM-compatible networks, including Arbitrum One via Arbiscan. All requests include a chainid parameter to select the target network. related: - Chain ID - API Key - Arbiscan - term: Event Log definition: >- A structured record emitted by a smart contract during transaction execution, containing indexed topics (for filtering) and non-indexed data. Event logs are permanently stored on-chain and can be queried by contract address, topic hash, and block range via the Arbiscan logs API. related: - Smart Contract - Token Transfer - Topic - term: Topic definition: >- An indexed field within an event log, represented as a 32-byte hex value. The first topic (topic0) is always the keccak-256 hash of the event signature. Additional topics (topic1, topic2, topic3) are the indexed parameters of the event. related: - Event Log - keccak-256 - Smart Contract - term: Sequencer definition: >- The entity responsible for ordering and batching transactions on Arbitrum One before submitting them to Ethereum mainnet. The sequencer provides fast transaction confirmations (typically under 1 second) and determines transaction ordering within each block. related: - Arbitrum One - Optimistic Rollup - Block - term: Block Explorer definition: >- A web application and API platform that indexes and provides searchable access to blockchain data including transactions, addresses, blocks, smart contracts, and tokens. Arbiscan is the official block explorer for Arbitrum One. related: - Arbiscan - Transaction - Smart Contract