TevmClient

TevmClient: object

Deprecated

This type has been superseded by Provider types from @tevm/decorators package The docs have not been updated to reflect this change if you are looking at this

A local EVM instance running in the browser, Bun, or Node.js. Akin to anvil or ganache. The TevmClient interface is a unified interface that all Clients implement. This provides a consistent developer experience no matter how you are using Tevm.

Type declaration

call

call: CallHandler

Executes a call against the VM. It is similar to eth_call but has more options for controlling the execution environment

By default it does not modify the state after the call is complete but this can be configured.

Example

const res = tevm.call({
  to: '0x123...',
  data: '0x123...',
  from: '0x123...',
  gas: 1000000,
  gasPrice: 1n,
  skipBalance: true,
}

contract

contract: ContractHandler

Executes a contract call against the VM. It is similar to eth_call but has more options for controlling the execution environment along with a typesafe API for creating the call via the contract abi.

The contract must already be deployed. Otherwise see script which executes calls against undeployed contracts

Example

const res = await tevm.contract({
  to: '0x123...',
  abi: [...],
  function: 'run',
  args: ['world']
  from: '0x123...',
  gas: 1000000,
  gasPrice: 1n,
  skipBalance: true,
}
console.log(res.data) // "hello"

dumpState

dumpState: DumpStateHandler

Dumps the current state of the VM into a JSON-seralizable object

State can be dumped as follows

Examples

const {state} = await tevm.dumpState()
fs.writeFileSync('state.json', JSON.stringify(state))

And then loaded as follows

const state = JSON.parse(fs.readFileSync('state.json'))
await tevm.loadState({state})

eth

eth: object

Standard JSON-RPC methods for interacting with the VM

See

JSON-RPC

eth.blockNumber

eth.blockNumber: EthBlockNumberHandler

Returns the current block number Set the tag to a block number or block hash to get the balance at that block Block tag defaults to ‘pending’ tag which is the optimistic state of the VM

See

JSON-RPC

Example

const blockNumber = await tevm.eth.blockNumber()
console.log(blockNumber) // 0n

eth.call

eth.call: EthCallHandler

Executes a call without modifying the state Set the tag to a block number or block hash to get the balance at that block Block tag defaults to ‘pending’ tag which is the optimistic state of the VM

See

JSON-RPC

Example

const res = await tevm.eth.call({to: '0x123...', data: '0x123...'})
console.log(res) // "0x..."

eth.chainId

eth.chainId: EthChainIdHandler

Returns the current chain id Set the tag to a block number or block hash to get the balance at that block Block tag defaults to ‘pending’ tag which is the optimistic state of the VM

See

JSON-RPC

Example

const chainId = await tevm.eth.chainId()
console.log(chainId) // 10n

eth.gasPrice

eth.gasPrice: EthGasPriceHandler

Returns the current gas price Set the tag to a block number or block hash to get the balance at that block Block tag defaults to ‘pending’ tag which is the optimistic state of the VM

See

JSON-RPC

Example

const gasPrice = await tevm.eth.gasPrice()
console.log(gasPrice) // 0n

eth.getBalance

eth.getBalance: EthGetBalanceHandler

Returns the balance of a given address Set the tag to a block number or block hash to get the balance at that block Block tag defaults to ‘pending’ tag which is the optimistic state of the VM

See

JSON-RPC

Example

const balance = await tevm.eth.getBalance({address: '0x123...', tag: 'pending'})
console.log(gasPrice) // 0n

eth.getCode

eth.getCode: EthGetCodeHandler

Returns code at a given address Set the tag to a block number or block hash to get the balance at that block Block tag defaults to ‘pending’ tag which is the optimistic state of the VM

See

JSON-RPC

Example

const code = await tevm.eth.getCode({address: '0x123...'})

eth.getStorageAt

eth.getStorageAt: EthGetStorageAtHandler

Returns storage at a given address and slot Set the tag to a block number or block hash to get the balance at that block Block tag defaults to ‘pending’ tag which is the optimistic state of the VM

See

JSON-RPC

Example

const storageValue = await tevm.eth.getStorageAt({address: '0x123...', position: 0})

getAccount

getAccount: GetAccountHandler

Gets the state of a specific ethereum address

Example

const res = tevm.getAccount({address: '0x123...'})
console.log(res.deployedBytecode)
console.log(res.nonce)
console.log(res.balance)

loadState

loadState: LoadStateHandler

Loads a previously dumped state into the VM

State can be dumped as follows

Examples

const {state} = await tevm.dumpState()
fs.writeFileSync('state.json', JSON.stringify(state))

And then loaded as follows

const state = JSON.parse(fs.readFileSync('state.json'))
await tevm.loadState({state})

request

request: TevmJsonRpcRequestHandler

Request handler for JSON-RPC requests. Most users will want to use the actions api instead of this method directly

Example

const blockNumberResponse = await tevm.request({
  method: 'eth_blockNumber',
  params: []
  id: 1
  jsonrpc: '2.0'
})
const accountResponse = await tevm.request({
  method: 'tevm_getAccount',
  params: [{address: '0x123...'}],
  id: 1,
  jsonrpc: '2.0',
})

requestBulk

requestBulk: TevmJsonRpcBulkRequestHandler

Bulk request handler for JSON-RPC requests. Takes an array of requests and returns an array of results. Bulk requests are currently handled in parallel which can cause issues if the requests are expected to run sequentially or interphere with each other. An option for configuring requests sequentially or in parallel will be added in the future.

Currently is not very generic with regard to input and output types.

Experimental

This API should not be used in production and may be trimmed from a public release.

Example

const [blockNumberResponse, gasPriceResponse] = await tevm.requestBulk([{
 method: 'eth_blockNumber',
 params: []
 id: 1
 jsonrpc: '2.0'
}, {
 method: 'eth_gasPrice',
 params: []
 id: 1
 jsonrpc: '2.0'
}])

tevm_* methods

tevm_call

request - CallJsonRpcRequest response - CallJsonRpcResponse

tevm_getAccount

request - GetAccountJsonRpcRequest response - GetAccountJsonRpcResponse

tevm_setAccount

request - SetAccountJsonRpcRequest response - SetAccountJsonRpcResponse

tevm_fork

request - ForkJsonRpcRequest response - ForkJsonRpcResponse

debug_* methods

debug_traceCall

request - DebugTraceCallJsonRpcRequest response - DebugTraceCallJsonRpcResponse

eth_* methods

eth_blockNumber

request - EthBlockNumberJsonRpcRequest response - EthBlockNumberJsonRpcResponse

eth_chainId

request - EthChainIdJsonRpcRequest response - EthChainIdJsonRpcResponse

eth_getCode

request - EthGetCodeJsonRpcRequest response - EthGetCodeJsonRpcResponse

eth_getStorageAt

request - EthGetStorageAtJsonRpcRequest response - EthGetStorageAtJsonRpcResponse

eth_gasPrice

request - EthGasPriceJsonRpcRequest response - EthGasPriceJsonRpcResponse

eth_getBalance

request - EthGetBalanceJsonRpcRequest response - EthGetBalanceJsonRpcResponse

setAccount

setAccount: SetAccountHandler

Sets the state of a specific ethereum address

Example

import {parseEther} from 'tevm'

await tevm.setAccount({
 address: '0x123...',
 deployedBytecode: '0x6080604...',
 balance: parseEther('1.0')
})

See

TevmClient guide for more documentation on clients

JSON-RPC

Tevm exposes a JSON-RPC interface for interacting with the EVM via the TevmClient.request

Examples

import {createMemoryClient, type Tevm} from 'tevm'

const tevm: Tevm = createMemoryClient()

await tevm.request({
  method: 'eth_blockNumber',
  params: [],
  id: 1,
  jsonrpc: '2.0',
}) // 0n

Actions

TevmClient exposes a higher level actions based api similar to viem for interacting with TevmClient in a typesasafe ergonomic way.

// same as eth_blockNumber example
const account = await tevm.account({address: `0x${'0'.repeat(40)}`})
console.log(account.balance) // 0n

Ethereum actions

Ethereum actions are namespaced under TevmClient.eth

const blockNumber = await tevm.eth.blockNumber()
console.log(blockNumber) // 0n

Anvil hardhat and ganache compatibility

Will have anvil_* ganache_* and hardhat_* JSON-RPC compatibility in future versions

Defined in

TevmClient.ts:131