Build reliable apps & libraries with lightweight, composable, and type-safe modules that interface with Ethereum

npm i viem

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1.7k

coverage

100%

license

MIT

Modular

Composable modules to build applications & libraries with speed

Lightweight

Tiny bundle size optimized for tree-shaking

Performant

Optimized architecture compared to alternative libraries

Typed APIs

Flexible programmatic APIs with extensive TypeScript typing

Overview

// 1. Import modules.
import { 
function createPublicClient<transport extends Transport, chain extends Chain | undefined = undefined>(parameters: PublicClientConfig<transport, chain>): PublicClient<transport, chain>Creates a Public Client with a given Transport configured for a Chain.
Docs: https://viem.sh/docs/clients/public
A Public Client is an interface to "public" JSON-RPC API methods such as retrieving block numbers, transactions, reading from smart contracts, etc through Public Actions.
createPublicClient, 
function http(url?: string, config?: HttpTransportConfig): HttpTransport
http } from 'viem'
import { 
const mainnet: {
  blockExplorers: {
    readonly default: {
      readonly name: "Etherscan";
      readonly url: "https://etherscan.io";
      readonly apiUrl: "https://api.etherscan.io/api";
    };
  };
  contracts: {
    readonly ensRegistry: {
      readonly address: "0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e";
    };
    readonly ensUniversalResolver: {
      readonly address: "0xc0497E381f536Be9ce14B0dD3817cBcAe57d2F62";
      readonly blockCreated: 16966585;
    };
    readonly multicall3: {
      readonly address: "0xca11bde05977b3631167028862be2a173976ca11";
      readonly blockCreated: 14353601;
    };
  };
  id: 1;
  name: "Ethereum";
  nativeCurrency: {
    readonly name: "Ether";
    readonly symbol: "ETH";
    readonly decimals: 18;
  };
  rpcUrls: {
    readonly default: {
      readonly http: readonly ["https://cloudflare-eth.com"];
    };
  };
  sourceId?: number | undefined;
  testnet?: boolean | undefined;
  formatters?: undefined;
  serializers?: import("../../index.js").ChainSerializers<undefined> | undefined;
  fees?: import("../../index.js").ChainFees<undefined> | undefined;
}
mainnet } from 'viem/chains'
 
// 2. Set up your client with desired chain & transport.
const 
const client: {
  account: undefined;
  batch?: {
    multicall?: boolean | {
      batchSize?: number | undefined;
      wait?: number | undefined;
    } | undefined;
  } | undefined;
  cacheTime: number;
  chain: {
    blockExplorers: {
      ...;
    };
    ... 9 more ...;
    fees?: ChainFees<...> | undefined;
  };
  ... 53 more ...;
  extend: <const client extends {
    ...;
  } & Partial<...>>(fn: (client: Client<...>) => client) => Client<...>;
}
client = 
createPublicClient<HttpTransport, {
  blockExplorers: {
    readonly default: {
      readonly name: "Etherscan";
      readonly url: "https://etherscan.io";
      readonly apiUrl: "https://api.etherscan.io/api";
    };
  };
  ... 9 more ...;
  fees?: ChainFees<...> | undefined;
}>(parameters: {
  ...;
}): {
  ...;
}Creates a Public Client with a given Transport configured for a Chain.
Docs: https://viem.sh/docs/clients/public
A Public Client is an interface to "public" JSON-RPC API methods such as retrieving block numbers, transactions, reading from smart contracts, etc through Public Actions.
createPublicClient({
  
chain?: Chain | {
  blockExplorers: {
    ...;
  };
  ... 9 more ...;
  fees?: ChainFees<...> | undefined;
} | undefinedChain for the client.
chain: 
const mainnet: {
  blockExplorers: {
    readonly default: {
      readonly name: "Etherscan";
      readonly url: "https://etherscan.io";
      readonly apiUrl: "https://api.etherscan.io/api";
    };
  };
  contracts: {
    readonly ensRegistry: {
      readonly address: "0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e";
    };
    readonly ensUniversalResolver: {
      readonly address: "0xc0497E381f536Be9ce14B0dD3817cBcAe57d2F62";
      readonly blockCreated: 16966585;
    };
    readonly multicall3: {
      readonly address: "0xca11bde05977b3631167028862be2a173976ca11";
      readonly blockCreated: 14353601;
    };
  };
  id: 1;
  name: "Ethereum";
  nativeCurrency: {
    readonly name: "Ether";
    readonly symbol: "ETH";
    readonly decimals: 18;
  };
  rpcUrls: {
    readonly default: {
      readonly http: readonly ["https://cloudflare-eth.com"];
    };
  };
  sourceId?: number | undefined;
  testnet?: boolean | undefined;
  formatters?: undefined;
  serializers?: import("../../index.js").ChainSerializers<undefined> | undefined;
  fees?: import("../../index.js").ChainFees<undefined> | undefined;
}
mainnet,
  
transport: HttpTransportThe RPC transport
transport: 
function http(url?: string | undefined, config?: HttpTransportConfig | undefined): HttpTransport
http(),
})
 
// 3. Consume an action!
const 
const blockNumber: bigint
blockNumber = await 
const client: {
  account: undefined;
  batch?: {
    multicall?: boolean | {
      batchSize?: number | undefined;
      wait?: number | undefined;
    } | undefined;
  } | undefined;
  cacheTime: number;
  chain: {
    blockExplorers: {
      ...;
    };
    ... 9 more ...;
    fees?: ChainFees<...> | undefined;
  };
  ... 53 more ...;
  extend: <const client extends {
    ...;
  } & Partial<...>>(fn: (client: Client<...>) => client) => Client<...>;
}
client.
getBlockNumber: (args?: GetBlockNumberParameters | undefined) => Promise<bigint>Returns the number of the most recent block seen.
Docs: https://viem.sh/docs/actions/public/getBlockNumber
Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/blocks/fetching-blocks
JSON-RPC Methods: eth_blockNumber
getBlockNumber()