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Chain Ethereum chain configuration objects with network metadata, RPC endpoints, and explorer information.
Learn about chain IDs, replay attack prevention, and network identification in the Fundamentals guide . Overview Branded type representing Ethereum chain configurations. Provides chain constants, metadata, and lookup utilities for Ethereum networks. Zero-overhead design supports both tree-shakeable namespace methods and class instances.Quick Start Types class Chain { // Constructors (→ /primitives/chain/constructors) static from ( chain : Chain ) : Chain static fromId ( id : number ) : Chain | undefined // Lookup (→ /primitives/chain/chain-lookup) static byId : Record < number , Chain > }
Source: Chain.js:14-36 export interface Chain { name : string chain : string chainId : number networkId ?: number shortName : string rpc : string [] nativeCurrency : NativeCurrency infoURL ?: string explorers ?: Explorer [] [ key : string ] : any } export interface NativeCurrency { name : string symbol : string decimals : number [ key : string ] : any } export interface Explorer { name : string url : string standard ?: string [ key : string ] : any }
Chain configuration object extending from @tevm/chains . Provides complete chain metadata including network name, chain ID, RPC endpoints, native currency details, and block explorer URLs. Source: ChainType.ts:1 Chain Constants Chain objects imported from @tevm/chains :
import { // Mainnets flr14 , quai9 , injective1776 , ronin2020 , moca2288 , // Popular networks (via chain ID) // Use Chain.fromId(id) or Chain.byId[id] } from '@tevm/chains' // Access chain metadata console . log ( quai9 . name ) // "Quai Mainnet" console . log ( quai9 . chainId ) // 9 console . log ( quai9 . nativeCurrency . symbol ) // "QUAI" // Use with Chain constructor const chain = Chain ( quai9 )
Available constants:
800+ chain configurations from @tevm/chains
Includes testnets, mainnets, L2s, and sidechains
Each constant includes full metadata (RPC, explorer, currency)
See @tevm/chains documentation for complete list.
API Methods Core Operations
fundamentals - Learn chain IDs, replay attack prevention, and network identificationconstructors - Create Chain instances from chain objects and chain IDschain-lookup - Look up chains by ID using fromId() and byId recordmetadata - Access chain properties: name, chainId, RPC, explorers, currency
Advanced Features Chain is a lightweight wrapper around plain JavaScript objects from @tevm/chains. The Chain class adds prototype methods while keeping the underlying data structure simple and serializable.
Address Ethereum address type for contract and account addresses.
View Address → Branded Types Zero-overhead type branding pattern used throughout primitives.
View Branded Types → Denomination Wei, Gwei, and Ether types with currency conversions.
View Denomination → FeeMarket EIP-1559 gas pricing with base and priority fees.
View FeeMarket → Hardfork Ethereum network upgrades and protocol versions.
View Hardfork → Transaction Transaction creation and signing across networks.
View Transaction → 
