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Custom Transport

A function to create a Custom Transport for a Client

The custom Transport accepts an EIP-1193 request function as a parameter. This transport is useful for integrating with injected wallets, wallets that provide an EIP-1193 provider (eg. WalletConnect or Coinbase SDK), or even providing your own custom request function.

Import

import { custom } from 'viem'

Usage

You can use any EIP-1193 compatible Ethereum Provider with the custom Transport:

import { createWalletClient, custom } from 'viem'
import { mainnet } from 'viem/chains'
 
const client = createWalletClient({
  chain: mainnet,
  transport: custom(window.ethereum!)
})

Or you can define your own:

import { createWalletClient, custom } from 'viem'
import { mainnet } from 'viem/chains'
import { customRpc } from './rpc'
 
const client = createWalletClient({ 
  chain: mainnet,
  transport: custom({
    async request({ method, params }) {
      const response = await customRpc.request(method, params)
      return response
    }
  })
})

Parameters

provider

  • Type: custom

An EIP-1193 request function function.

import { customRpc } from './rpc'
 
const transport = custom({
  async request({ method, params }) { 
    const response = await customRpc.request(method, params)
    return response
  }
})

key (optional)

  • Type: string
  • Default: "custom"

A key for the Transport.

const transport = custom(
  window.ethereum!,
  { 
    key: 'windowProvider', 
  }
)

name (optional)

  • Type: string
  • Default: "Ethereum Provider"

A name for the Transport

const transport = custom(
  window.ethereum!,
  { 
    name: 'Window Ethereum Provider', 
  }
)

retryCount (optional)

  • Type: number
  • Default: 3

The max number of times to retry when a request fails.

const transport = custom(window.ethereum!, {
  retryCount: 5, 
})

retryDelay (optional)

  • Type: number
  • Default: 150

The base delay (in ms) between retries. By default, the Transport will use exponential backoff (~~(1 << count) * retryDelay), which means the time between retries is not constant.

const transport = custom(window.ethereum!, {
  retryDelay: 100, 
})

Gotchas