Custom Transport

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'

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)
})

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
    }
  })
})

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
  }
})

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', 
  }
)

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', 
  }
)

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, 
})

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, 
})

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

Gotchas

If you are pairing the custom Transport with a Public Client, ensure that your provider supports Public Actions.

Custom Transport ​

Import ​

Usage ​

Parameters ​

provider ​

key (optional) ​

name (optional) ​

retryCount (optional) ​

retryDelay (optional) ​

Gotchas ​