createExpressMiddleware

createExpressMiddleware(client): RequestHandler<ParamsDictionary, any, any, ParsedQs, Record<string, any>>

Creates express middleware for a Tevm JSON-RPC server

Parameters

• client

• client._tevm: object & EIP1193Events & object & Eip1193RequestProvider & TevmActionsApi & object

• client.account: undefined

The Account of the Client.

• client.batch?

Flags for batch settings.

• client.batch.multicall?: boolean | object

Toggle to enable eth_call multicall aggregation.

• client.cacheTime: number

Time (in ms) that cached data will remain in memory.

• client.call

Executes a new message call immediately without submitting a transaction to the network.

• Docs: https://viem.sh/docs/actions/public/call
• JSON-RPC Methods: eth_call

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const data = await client.call({
  account: '0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266',
  data: '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2',
  to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
})

• client.ccipRead?: false | object

CCIP Read configuration.

• client.chain: undefined

Chain for the client.

• client.createBlockFilter

Creates a Filter to listen for new block hashes that can be used with getFilterChanges.

• Docs: https://viem.sh/docs/actions/public/createBlockFilter
• JSON-RPC Methods: eth_newBlockFilter

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const filter = await createBlockFilter(client)
// { id: "0x345a6572337856574a76364e457a4366", type: 'block' }

• client.createContractEventFilter

Creates a Filter to retrieve event logs that can be used with getFilterChanges or getFilterLogs.

• Docs: https://viem.sh/docs/contract/createContractEventFilter

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const filter = await client.createContractEventFilter({
  abi: parseAbi(['event Transfer(address indexed, address indexed, uint256)']),
})

• client.createEventFilter

Creates a Filter to listen for new events that can be used with getFilterChanges.

• Docs: https://viem.sh/docs/actions/public/createEventFilter
• JSON-RPC Methods: eth_newFilter

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const filter = await client.createEventFilter({
  address: '0xfba3912ca04dd458c843e2ee08967fc04f3579c2',
})

• client.createPendingTransactionFilter

Creates a Filter to listen for new pending transaction hashes that can be used with getFilterChanges.

• Docs: https://viem.sh/docs/actions/public/createPendingTransactionFilter
• JSON-RPC Methods: eth_newPendingTransactionFilter

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const filter = await client.createPendingTransactionFilter()
// { id: "0x345a6572337856574a76364e457a4366", type: 'transaction' }

• client.estimateContractGas

Estimates the gas required to successfully execute a contract write function call.

• Docs: https://viem.sh/docs/contract/estimateContractGas

Remarks

Internally, uses a Public Client to call the estimateGas action with ABI-encoded data.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const gas = await client.estimateContractGas({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: parseAbi(['function mint() public']),
  functionName: 'mint',
  account: '0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266',
})

• client.estimateFeesPerGas

Returns an estimate for the fees per gas for a transaction to be included in the next block.

• Docs: https://viem.sh/docs/actions/public/estimateFeesPerGas

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const maxPriorityFeePerGas = await client.estimateFeesPerGas()
// { maxFeePerGas: ..., maxPriorityFeePerGas: ... }

• client.estimateGas

Estimates the gas necessary to complete a transaction without submitting it to the network.

• Docs: https://viem.sh/docs/actions/public/estimateGas
• JSON-RPC Methods: eth_estimateGas

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const gasEstimate = await client.estimateGas({
  account: '0xA0Cf798816D4b9b9866b5330EEa46a18382f251e',
  to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
  value: parseEther('1'),
})

• client.estimateMaxPriorityFeePerGas

Returns an estimate for the max priority fee per gas (in wei) for a transaction to be included in the next block.

• Docs: https://viem.sh/docs/actions/public/estimateMaxPriorityFeePerGas

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const maxPriorityFeePerGas = await client.estimateMaxPriorityFeePerGas()
// 10000000n

• client.extend

• client.getBalance

Returns the balance of an address in wei.

• Docs: https://viem.sh/docs/actions/public/getBalance
• JSON-RPC Methods: eth_getBalance

Remarks

You can convert the balance to ether units with formatEther.

const balance = await getBalance(client, {
  address: '0xA0Cf798816D4b9b9866b5330EEa46a18382f251e',
  blockTag: 'safe'
})
const balanceAsEther = formatEther(balance)
// "6.942"

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const balance = await client.getBalance({
  address: '0xA0Cf798816D4b9b9866b5330EEa46a18382f251e',
})
// 10000000000000000000000n (wei)

• client.getBlobBaseFee

Returns the base fee per blob gas in wei.

• Docs: https://viem.sh/docs/actions/public/getBlobBaseFee
• JSON-RPC Methods: eth_blobBaseFee

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const blobBaseFee = await client.getBlobBaseFee()

• client.getBlock

Returns information about a block at a block number, hash, or tag.

• Docs: https://viem.sh/docs/actions/public/getBlock
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/blocks/fetching-blocks
• JSON-RPC Methods:
  • Calls eth_getBlockByNumber for blockNumber & blockTag.
  • Calls eth_getBlockByHash for blockHash.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const block = await client.getBlock()

• client.getBlockNumber

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

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const blockNumber = await client.getBlockNumber()
// 69420n

• client.getBlockTransactionCount

Returns the number of Transactions at a block number, hash, or tag.

• Docs: https://viem.sh/docs/actions/public/getBlockTransactionCount
• JSON-RPC Methods:
  • Calls eth_getBlockTransactionCountByNumber for blockNumber & blockTag.
  • Calls eth_getBlockTransactionCountByHash for blockHash.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const count = await client.getBlockTransactionCount()

• client.getBytecode

Retrieves the bytecode at an address.

• Docs: https://viem.sh/docs/contract/getBytecode
• JSON-RPC Methods: eth_getCode

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const code = await client.getBytecode({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
})

• client.getChainId

Returns the chain ID associated with the current network.

• Docs: https://viem.sh/docs/actions/public/getChainId
• JSON-RPC Methods: eth_chainId

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const chainId = await client.getChainId()
// 1

• client.getContractEvents

Returns a list of event logs emitted by a contract.

• Docs: https://viem.sh/docs/actions/public/getContractEvents
• JSON-RPC Methods: eth_getLogs

Example

import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'
import { wagmiAbi } from './abi'

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const logs = await client.getContractEvents(client, {
 address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
 abi: wagmiAbi,
 eventName: 'Transfer'
})

• client.getEnsAddress

Gets address for ENS name.

• Docs: https://viem.sh/docs/ens/actions/getEnsAddress
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/ens

Remarks

Calls resolve(bytes, bytes) on ENS Universal Resolver Contract.

Since ENS names prohibit certain forbidden characters (e.g. underscore) and have other validation rules, you likely want to normalize ENS names with UTS-46 normalization before passing them to getEnsAddress. You can use the built-in normalize function for this.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const ensAddress = await client.getEnsAddress({
  name: normalize('wevm.eth'),
})
// '0xd2135CfB216b74109775236E36d4b433F1DF507B'

• client.getEnsAvatar

Gets the avatar of an ENS name.

• Docs: https://viem.sh/docs/ens/actions/getEnsAvatar
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/ens

Remarks

Calls getEnsText with key set to 'avatar'.

Since ENS names prohibit certain forbidden characters (e.g. underscore) and have other validation rules, you likely want to normalize ENS names with UTS-46 normalization before passing them to getEnsAddress. You can use the built-in normalize function for this.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const ensAvatar = await client.getEnsAvatar({
  name: normalize('wevm.eth'),
})
// 'https://ipfs.io/ipfs/Qma8mnp6xV3J2cRNf3mTth5C8nV11CAnceVinc3y8jSbio'

• client.getEnsName

Gets primary name for specified address.

• Docs: https://viem.sh/docs/ens/actions/getEnsName
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/ens

Remarks

Calls reverse(bytes) on ENS Universal Resolver Contract to “reverse resolve” the address to the primary ENS name.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const ensName = await client.getEnsName({
  address: '0xd2135CfB216b74109775236E36d4b433F1DF507B',
})
// 'wevm.eth'

• client.getEnsResolver

Gets resolver for ENS name.

• Docs: https://viem.sh/docs/ens/actions/getEnsResolver
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/ens

Remarks

Calls findResolver(bytes) on ENS Universal Resolver Contract to retrieve the resolver of an ENS name.

Since ENS names prohibit certain forbidden characters (e.g. underscore) and have other validation rules, you likely want to normalize ENS names with UTS-46 normalization before passing them to getEnsAddress. You can use the built-in normalize function for this.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const resolverAddress = await client.getEnsResolver({
  name: normalize('wevm.eth'),
})
// '0x4976fb03C32e5B8cfe2b6cCB31c09Ba78EBaBa41'

• client.getEnsText

Gets a text record for specified ENS name.

• Docs: https://viem.sh/docs/ens/actions/getEnsResolver
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/ens

Remarks

Calls resolve(bytes, bytes) on ENS Universal Resolver Contract.

Since ENS names prohibit certain forbidden characters (e.g. underscore) and have other validation rules, you likely want to normalize ENS names with UTS-46 normalization before passing them to getEnsAddress. You can use the built-in normalize function for this.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const twitterRecord = await client.getEnsText({
  name: normalize('wevm.eth'),
  key: 'com.twitter',
})
// 'wevm_dev'

• client.getFeeHistory

Returns a collection of historical gas information.

• Docs: https://viem.sh/docs/actions/public/getFeeHistory
• JSON-RPC Methods: eth_feeHistory

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const feeHistory = await client.getFeeHistory({
  blockCount: 4,
  rewardPercentiles: [25, 75],
})

• client.getFilterChanges

Returns a list of logs or hashes based on a Filter since the last time it was called.

• Docs: https://viem.sh/docs/actions/public/getFilterChanges
• JSON-RPC Methods: eth_getFilterChanges

Remarks

A Filter can be created from the following actions:

• createBlockFilter
• createContractEventFilter
• createEventFilter
• createPendingTransactionFilter

Depending on the type of filter, the return value will be different:

• If the filter was created with createContractEventFilter or createEventFilter, it returns a list of logs.
• If the filter was created with createPendingTransactionFilter, it returns a list of transaction hashes.
• If the filter was created with createBlockFilter, it returns a list of block hashes.

Examples

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const filter = await client.createBlockFilter()
const hashes = await client.getFilterChanges({ filter })

// Contract Events
import { createPublicClient, http, parseAbi } from 'viem'
import { mainnet } from 'viem/chains'

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const filter = await client.createContractEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  abi: parseAbi(['event Transfer(address indexed, address indexed, uint256)']),
  eventName: 'Transfer',
})
const logs = await client.getFilterChanges({ filter })

// Raw Events
import { createPublicClient, http, parseAbiItem } from 'viem'
import { mainnet } from 'viem/chains'

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const filter = await client.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed, address indexed, uint256)'),
})
const logs = await client.getFilterChanges({ filter })

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const filter = await client.createPendingTransactionFilter()
const hashes = await client.getFilterChanges({ filter })

• client.getFilterLogs

Returns a list of event logs since the filter was created.

• Docs: https://viem.sh/docs/actions/public/getFilterLogs
• JSON-RPC Methods: eth_getFilterLogs

Remarks

getFilterLogs is only compatible with event filters.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const filter = await client.createEventFilter({
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  event: parseAbiItem('event Transfer(address indexed, address indexed, uint256)'),
})
const logs = await client.getFilterLogs({ filter })

• client.getGasPrice

Returns the current price of gas (in wei).

• Docs: https://viem.sh/docs/actions/public/getGasPrice
• JSON-RPC Methods: eth_gasPrice

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const gasPrice = await client.getGasPrice()

• client.getLogs

Returns a list of event logs matching the provided parameters.

• Docs: https://viem.sh/docs/actions/public/getLogs
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/filters-and-logs/event-logs
• JSON-RPC Methods: eth_getLogs

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const logs = await client.getLogs()

• client.getProof

Returns the account and storage values of the specified account including the Merkle-proof.

• Docs: https://viem.sh/docs/actions/public/getProof
• JSON-RPC Methods:
  • Calls eth_getProof

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const block = await client.getProof({
 address: '0x...',
 storageKeys: ['0x...'],
})

• client.getStorageAt

Returns the value from a storage slot at a given address.

• Docs: https://viem.sh/docs/contract/getStorageAt
• JSON-RPC Methods: eth_getStorageAt

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const code = await client.getStorageAt({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  slot: toHex(0),
})

• client.getTransaction

Returns information about a Transaction given a hash or block identifier.

• Docs: https://viem.sh/docs/actions/public/getTransaction
• Example: https://stackblitz.com/github/wevm/viem/tree/main/examples/transactions/fetching-transactions
• JSON-RPC Methods: eth_getTransactionByHash

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const transaction = await client.getTransaction({
  hash: '0x4ca7ee652d57678f26e887c149ab0735f41de37bcad58c9f6d3ed5824f15b74d',
})

• client.getTransactionConfirmations

Returns the number of blocks passed (confirmations) since the transaction was processed on a block.

• Docs: https://viem.sh/docs/actions/public/getTransactionConfirmations
• Example: https://stackblitz.com/github/wevm/viem/tree/main/examples/transactions/fetching-transactions
• JSON-RPC Methods: eth_getTransactionConfirmations

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const confirmations = await client.getTransactionConfirmations({
  hash: '0x4ca7ee652d57678f26e887c149ab0735f41de37bcad58c9f6d3ed5824f15b74d',
})

• client.getTransactionCount

Returns the number of Transactions an Account has broadcast / sent.

• Docs: https://viem.sh/docs/actions/public/getTransactionCount
• JSON-RPC Methods: eth_getTransactionCount

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const transactionCount = await client.getTransactionCount({
  address: '0xA0Cf798816D4b9b9866b5330EEa46a18382f251e',
})

• client.getTransactionReceipt

Returns the Transaction Receipt given a Transaction hash.

• Docs: https://viem.sh/docs/actions/public/getTransactionReceipt
• Example: https://stackblitz.com/github/wevm/viem/tree/main/examples/transactions/fetching-transactions
• JSON-RPC Methods: eth_getTransactionReceipt

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const transactionReceipt = await client.getTransactionReceipt({
  hash: '0x4ca7ee652d57678f26e887c149ab0735f41de37bcad58c9f6d3ed5824f15b74d',
})

• client.key: string

A key for the client.

• client.multicall

Similar to readContract, but batches up multiple functions on a contract in a single RPC call via the multicall3 contract.

• Docs: https://viem.sh/docs/contract/multicall

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const abi = parseAbi([
  'function balanceOf(address) view returns (uint256)',
  'function totalSupply() view returns (uint256)',
])
const result = await client.multicall({
  contracts: [
    {
      address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
      abi,
      functionName: 'balanceOf',
      args: ['0xA0Cf798816D4b9b9866b5330EEa46a18382f251e'],
    },
    {
      address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
      abi,
      functionName: 'totalSupply',
    },
  ],
})
// [{ result: 424122n, status: 'success' }, { result: 1000000n, status: 'success' }]

• client.name: string

A name for the client.

• client.pollingInterval: number

Frequency (in ms) for polling enabled actions & events. Defaults to 4_000 milliseconds.

• client.prepareTransactionRequest

Prepares a transaction request for signing.

• Docs: https://viem.sh/docs/actions/wallet/prepareTransactionRequest

Examples

import { createWalletClient, custom } from 'viem'
import { mainnet } from 'viem/chains'

const client = createWalletClient({
  chain: mainnet,
  transport: custom(window.ethereum),
})
const request = await client.prepareTransactionRequest({
  account: '0xA0Cf798816D4b9b9866b5330EEa46a18382f251e',
  to: '0x0000000000000000000000000000000000000000',
  value: 1n,
})

// Account Hoisting
import { createWalletClient, http } from 'viem'
import { privateKeyToAccount } from 'viem/accounts'
import { mainnet } from 'viem/chains'

const client = createWalletClient({
  account: privateKeyToAccount('0x…'),
  chain: mainnet,
  transport: custom(window.ethereum),
})
const request = await client.prepareTransactionRequest({
  to: '0x0000000000000000000000000000000000000000',
  value: 1n,
})

• client.readContract

Calls a read-only function on a contract, and returns the response.

• Docs: https://viem.sh/docs/contract/readContract
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/contracts/reading-contracts

Remarks

A “read-only” function (constant function) on a Solidity contract is denoted by a view or pure keyword. They can only read the state of the contract, and cannot make any changes to it. Since read-only methods do not change the state of the contract, they do not require any gas to be executed, and can be called by any user without the need to pay for gas.

Internally, uses a Public Client to call the call action with ABI-encoded data.

Example

import { createPublicClient, http, parseAbi } from 'viem'
import { mainnet } from 'viem/chains'
import { readContract } from 'viem/contract'

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const result = await client.readContract({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: parseAbi(['function balanceOf(address) view returns (uint256)']),
  functionName: 'balanceOf',
  args: ['0xA0Cf798816D4b9b9866b5330EEa46a18382f251e'],
})
// 424122n

• client.request: EIP1193RequestFn<[object, object, object, object, object]>

Request function wrapped with friendly error handling

• client.sendRawTransaction

Sends a signed transaction to the network

• Docs: https://viem.sh/docs/actions/wallet/sendRawTransaction
• JSON-RPC Method: eth_sendRawTransaction

Example

import { createWalletClient, custom } from 'viem'
import { mainnet } from 'viem/chains'
import { sendRawTransaction } from 'viem/wallet'

const client = createWalletClient({
  chain: mainnet,
  transport: custom(window.ethereum),
})

const hash = await client.sendRawTransaction({
  serializedTransaction: '0x02f850018203118080825208808080c080a04012522854168b27e5dc3d5839bab5e6b39e1a0ffd343901ce1622e3d64b48f1a04e00902ae0502c4728cbf12156290df99c3ed7de85b1dbfe20b5c36931733a33'
})

• client.simulateContract

Simulates/validates a contract interaction. This is useful for retrieving return data and revert reasons of contract write functions.

• Docs: https://viem.sh/docs/contract/simulateContract
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/contracts/writing-to-contracts

Remarks

This function does not require gas to execute and does not change the state of the blockchain. It is almost identical to readContract, but also supports contract write functions.

Internally, uses a Public Client to call the call action with ABI-encoded data.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const result = await client.simulateContract({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: parseAbi(['function mint(uint32) view returns (uint32)']),
  functionName: 'mint',
  args: ['69420'],
  account: '0xA0Cf798816D4b9b9866b5330EEa46a18382f251e',
})

• client.tevmCall: CallHandler

• client.tevmContract: ContractHandler

• client.tevmDeploy: DeployHandler

• client.tevmDumpState: DumpStateHandler

• client.tevmForkUrl?: string

• client.tevmGetAccount: GetAccountHandler

• client.tevmLoadState: LoadStateHandler

• client.tevmMine: MineHandler

• client.tevmReady

• client.tevmScript: ScriptHandler

• client.tevmSetAccount: SetAccountHandler

• client.transport: TransportConfig<string, EIP1193RequestFn> & Record<string, any>

The RPC transport

• client.type: string

The type of client.

• client.uid: string

A unique ID for the client.

• client.uninstallFilter

Destroys a Filter that was created from one of the following Actions:

• createBlockFilter

• createEventFilter

• createPendingTransactionFilter

• Docs: https://viem.sh/docs/actions/public/uninstallFilter

• JSON-RPC Methods: eth_uninstallFilter

Example

import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'
import { createPendingTransactionFilter, uninstallFilter } from 'viem/public'

const filter = await client.createPendingTransactionFilter()
const uninstalled = await client.uninstallFilter({ filter })
// true

• client.verifyMessage

Verify that a message was signed by the provided address.

Compatible with Smart Contract Accounts & Externally Owned Accounts via ERC-6492.

• Docs https://viem.sh/docs/actions/public/verifyMessage

• client.verifySiweMessage

Verifies EIP-4361 formatted message was signed.

Compatible with Smart Contract Accounts & Externally Owned Accounts via ERC-6492.

• Docs https://viem.sh/docs/siwe/actions/verifySiweMessage

• client.verifyTypedData

Verify that typed data was signed by the provided address.

• Docs https://viem.sh/docs/actions/public/verifyTypedData

• client.waitForTransactionReceipt

Waits for the Transaction to be included on a Block (one confirmation), and then returns the Transaction Receipt. If the Transaction reverts, then the action will throw an error.

• Docs: https://viem.sh/docs/actions/public/waitForTransactionReceipt
• Example: https://stackblitz.com/github/wevm/viem/tree/main/examples/transactions/sending-transactions
• JSON-RPC Methods:
  • Polls eth_getTransactionReceipt on each block until it has been processed.
  • If a Transaction has been replaced:
    • Calls eth_getBlockByNumber and extracts the transactions
    • Checks if one of the Transactions is a replacement
    • If so, calls eth_getTransactionReceipt.

Remarks

The waitForTransactionReceipt action additionally supports Replacement detection (e.g. sped up Transactions).

Transactions can be replaced when a user modifies their transaction in their wallet (to speed up or cancel). Transactions are replaced when they are sent from the same nonce.

There are 3 types of Transaction Replacement reasons:

• repriced: The gas price has been modified (e.g. different maxFeePerGas)
• cancelled: The Transaction has been cancelled (e.g. value === 0n)
• replaced: The Transaction has been replaced (e.g. different value or data)

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const transactionReceipt = await client.waitForTransactionReceipt({
  hash: '0x4ca7ee652d57678f26e887c149ab0735f41de37bcad58c9f6d3ed5824f15b74d',
})

• client.watchBlockNumber

Watches and returns incoming block numbers.

• Docs: https://viem.sh/docs/actions/public/watchBlockNumber
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/blocks/watching-blocks
• JSON-RPC Methods:
  • When poll: true, calls eth_blockNumber on a polling interval.
  • When poll: false & WebSocket Transport, uses a WebSocket subscription via eth_subscribe and the "newHeads" event.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const unwatch = await client.watchBlockNumber({
  onBlockNumber: (blockNumber) => console.log(blockNumber),
})

• client.watchBlocks

Watches and returns information for incoming blocks.

• Docs: https://viem.sh/docs/actions/public/watchBlocks
• Examples: https://stackblitz.com/github/wevm/viem/tree/main/examples/blocks/watching-blocks
• JSON-RPC Methods:
  • When poll: true, calls eth_getBlockByNumber on a polling interval.
  • When poll: false & WebSocket Transport, uses a WebSocket subscription via eth_subscribe and the "newHeads" event.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const unwatch = await client.watchBlocks({
  onBlock: (block) => console.log(block),
})

• client.watchContractEvent

Watches and returns emitted contract event logs.

• Docs: https://viem.sh/docs/contract/watchContractEvent

Remarks

This Action will batch up all the event logs found within the pollingInterval, and invoke them via onLogs.

watchContractEvent will attempt to create an Event Filter and listen to changes to the Filter per polling interval, however, if the RPC Provider does not support Filters (e.g. eth_newFilter), then watchContractEvent will fall back to using getLogs instead.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const unwatch = client.watchContractEvent({
  address: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  abi: parseAbi(['event Transfer(address indexed from, address indexed to, uint256 value)']),
  eventName: 'Transfer',
  args: { from: '0xc961145a54C96E3aE9bAA048c4F4D6b04C13916b' },
  onLogs: (logs) => console.log(logs),
})

• client.watchEvent

Watches and returns emitted Event Logs.

• Docs: https://viem.sh/docs/actions/public/watchEvent
• JSON-RPC Methods:
  • RPC Provider supports eth_newFilter:
    • Calls eth_newFilter to create a filter (called on initialize).
    • On a polling interval, it will call eth_getFilterChanges.
  • RPC Provider does not support eth_newFilter:
    • Calls eth_getLogs for each block between the polling interval.

Remarks

This Action will batch up all the Event Logs found within the pollingInterval, and invoke them via onLogs.

watchEvent will attempt to create an Event Filter and listen to changes to the Filter per polling interval, however, if the RPC Provider does not support Filters (e.g. eth_newFilter), then watchEvent will fall back to using getLogs instead.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const unwatch = client.watchEvent({
  onLogs: (logs) => console.log(logs),
})

• client.watchPendingTransactions

Watches and returns pending transaction hashes.

• Docs: https://viem.sh/docs/actions/public/watchPendingTransactions
• JSON-RPC Methods:
  • When poll: true
    • Calls eth_newPendingTransactionFilter to initialize the filter.
    • Calls eth_getFilterChanges on a polling interval.
  • When poll: false & WebSocket Transport, uses a WebSocket subscription via eth_subscribe and the "newPendingTransactions" event.

Remarks

This Action will batch up all the pending transactions found within the pollingInterval, and invoke them via onTransactions.

Example

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

const client = createPublicClient({
  chain: mainnet,
  transport: http(),
})
const unwatch = await client.watchPendingTransactions({
  onTransactions: (hashes) => console.log(hashes),
})

Returns

RequestHandler<ParamsDictionary, any, any, ParsedQs, Record<string, any>>

Example

import express from 'express'
import { createExpressMiddleware } from 'tevm/server'
import { createMemoryClient } from 'tevm'

const tevm = createMemoryClient()

const app = express()
app.use(express.json())
app.use(createExpressMiddleware({ request: tevm.request }))
app.listen(8080, () => console.log('listening on 8080'))

After creating an express server it can be interacted with using any JSON-RPC client including viem, ethers or the built in tevm client

import { createClient } from 'tevm/client'

const client = createClient({
 url: 'http://localhost:8080'
 })

 const blockNumber = await client.eth.getBlockNumber()
 const chainId = await client.eth.getChainId()

Source

packages/server/src/adapters/createExpressMiddleware.js:34