Fallback Transport #

The fallback Transport consumes multiple Transports. If a Transport request fails, it will fall back to the next one in the list.

Import #

import { fallback } from 'viem'

Usage #

import { createPublicClient, fallback, http } from 'viem'
import { mainnet } from 'viem/chains'

const alchemy = http({ 
  url: 'https://eth-mainnet.g.alchemy.com/v2/...' 
})
const infura = http({ 
  url: 'https://mainnet.infura.io/v3/...' 
})

const client = createPublicClient({
  chain: mainnet,
  transport: fallback([alchemy, infura]),
})

Parameters #

retryCount (optional) #

• Type: number
• Default: 3

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

Note: The fallback will first try all the Transports before retrying.

const transport = fallback([alchemy, infura], {
  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 = fallback([alchemy, infura], {
  retryDelay: 100, 
})