Migrate from v1 to v2

Wagmi Core v2 redesigns the core APIs to mesh better with Viem. This major version transforms Wagmi into a light wrapper around Viem, sprinkling in multichain support and account management. As such, there are some breaking changes and deprecations to be aware of outlined in this guide.

To get started, install the latest version of Wagmi and it's required peer dependencies.

pnpmnpmyarnbun

bash

pnpm add @wagmi/core viem@2.x @wagmi/connectors

bash

npm install @wagmi/core viem@2.x @wagmi/connectors

bash

yarn add @wagmi/core viem@2.x @wagmi/connectors

bash

bun add @wagmi/core viem@2.x @wagmi/connectors

Wagmi Core v2 should be the last major version that will have this many actionable breaking changes.

Moving forward, new functionality will be opt-in with old functionality being deprecated alongside the new features. This means upgrading to the latest major versions will not require immediate changes.

Not ready to migrate yet?

The Wagmi Core v1 docs are still available at 1.x.wagmi.sh/core.

Dependencies

Dropped CommonJS support

Wagmi v2 no longer publishes a separate cjs tag since very few people use this tag and ESM is the future. See Sindre Sorhus' guide for more info about switching to ESM.

Actions

Removed `config` singleton

Before v2, when you called createConfig, it set a global config singleton that was used internally by actions. For v2, config is now a required first parameter for actions.

index.tsconfig.ts

import { getAccount, readContract } from '@wagmi/core'
import { parseAbi } from 'viem'
import { config } from './config'

const account = getAccount()
const account = getAccount(config)

const balanceOf = readContract({ 
const balanceOf = readContract(config, { 
  address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
  abi: parseAbi(['function balanceOf(address) view returns (uint256)']),
  functionName: 'balanceOf',
  args: ['0xd2135CfB216b74109775236E36d4b433F1DF507B'],
})

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

The previous global config singleton made it so you couldn't use multiple Config objects in the same project. In addition, we think passing config is more explicit and makes it easier to understand what's going on. Finally, types can be inferred directly from the config, like chain properties and more.

Removed `getContract`

Removed getContract export. Use Viem's getContract instead.

import { getContract } from '@wagmi/core'
import { getContract } from 'viem'

const contract = getContract()
const contract = getContract()

Removed `getNetwork` and `watchNetwork`

The getNetwork and watchNetwork actions were removed since the connected chain is typically based on the connected account.

Use config.chains instead to get chains.

index.tsconfig.ts

import { getNetwork } from '@wagmi/core'

const { chains } = getNetwork()
const chains = config.chains

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

Use getAccount and config.chains instead to get chain.

index.tsconfig.ts

import { getNetwork } from '@wagmi/core'
import { getAccount } from '@wagmi/core'
import { config } from './config'

const { chain } = getNetwork()
const { chainId } = getAccount(config)
const chain = chains.find(chain => chain.id === chainId)

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

Before v2, getNetwork().chain could result in an invalid chain if the active connector's chainId was not configured in the list of config.chains. Using getAccount and config.chains is more work, but ensures that chain is either valid or not defined. You can also use getAccount(config).chain if you don't care about the chain being undefined when not configured.

Use watchAccount instead of watchNetwork.

index.tsconfig.ts

import { watchNetwork } from '@wagmi/core'
import { watchAccount } from '@wagmi/core'
import { config } from './config'

const unwatch = watchNetwork((data) => console.log('Changed!', data))
const unwatch = watchAccount(config, { 
  onChange(data) { 
    const chains = config.chains
    const chain = chains.find(chain => chain.id === data.chainId)
  }, 
})

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

Removed `getWebSocketPublicClient` and `watchWebSocketPublicClient`

Viem Transports now determine the type of client that is returned. You can use getPublicClient and watchPublicClient to retrieve Viem PublicClient instances.

Alternatively, you can use getClient and watchClient to retrieve plain Viem Client instances. This is a better option for users that care about optimizing bundle size to be as small as possible.

Removed `watchReadContract`, `watchReadContracts`, and `watchReadMulticall`

Use watchBlockNumber along with readContract, readContracts, and multicall actions instead. Before v2, watchReadContract, watchReadContracts, and watchReadMulticall were all wrappers around watchBlockNumber and this simplifies the API.

index.tsconfig.ts

import { watchReadContract } from '@wagmi/core'
import { watchBlockNumber, readContract } from '@wagmi/core'
import { config } from './config'

const unwatch = watchReadContract(
  { 
    address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48', 
    abi: parseAbi(['function balanceOf(address) view returns (uint256)']), 
    functionName: 'balanceOf', 
    args: ['0xd2135CfB216b74109775236E36d4b433F1DF507B'], 
  },
  (result) => console.log('Changed!', result),
)
const unwatch = watchBlockNumber(config, { 
  onBlockNumber() { 
    const balanceOf = readContract(config, { 
      address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48', 
      abi: parseAbi(['function balanceOf(address) view returns (uint256)']), 
      functionName: 'balanceOf', 
      args: ['0xd2135CfB216b74109775236E36d4b433F1DF507B'], 
    })
    console.log('Changed!', balanceOf)
  }, 
})

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

Removed `fetchFeeData`

Removed fetchFeeData. Use estimateFeesPerGas instead.

index.tsconfig.ts

import { fetchFeeData } from '@wagmi/core'
import { estimateFeesPerGas } from '@wagmi/core'
import { config } from './config'

const result = await fetchFeeData()
const result = await estimateFeesPerGas(config)

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

Removed `prepareWriteContract`

Removed prepareWriteContract. Use simulateContract instead.

index.tsconfig.ts

import { prepareWriteContract } from '@wagmi/core'
import { simulateContract } from '@wagmi/core'
import { config } from './config'

const result = await prepareWriteContract({ ... })
const result = await simulateContract(config, { ... })

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

Removed `prepareSendTransaction`

Removed prepareSendTransaction. Use estimateGas instead.

index.tsconfig.ts

import { prepareSendTransaction } from '@wagmi/core'
import { estimateGas } from '@wagmi/core'
import { config } from './config'

const result = await prepareSendTransaction({ ... })
const result = await estimateGas(config, { ... })

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

Updated `sendTransaction` and `writeContract` return type

Updated sendTransaction and writeContract return type from { hash: `0x${string}` } to `0x${string}`.

const result = await sendTransaction({ hash: '0x...' })
result.hash
result

Updated `connect` return type

Updated connect return type from { account: Address; chain: { id: number; unsupported?: boolean }; connector: Connector } to { accounts: readonly Address[]; chainId: number }. This better reflects the ability to have multiple accounts per connector.

Renamed parameters and return types

All hook parameters and return types follow the naming pattern of [PascalCaseActionName]Parameters and [PascalCaseActionName]ReturnType. For example, GetAccountParameters and GetAccountReturnType.

import { GetAccountConfig, GetAccountResult } from '@wagmi/core'
import { GetAccountParameters, GetAccountReturnType } from '@wagmi/core'

Connectors

Moved Wagmi Connectors to peer dependencies

Wagmi Core v2 no longer exports connectors via the '@wagmi/core/connectors/*' entrypoints. Instead, you should install the @wagmi/connectors package.

pnpmnpmyarnbun

bash

pnpm add @wagmi/connectors

bash

npm install @wagmi/connectors

bash

yarn add @wagmi/connectors

bash

bun add @wagmi/connectors

And import connectors from there.

import { injected } from '@wagmi/connectors'

See the connectors documentation for more information.

Updated connector API

In order to maximize type-safety and ease of creating connectors, the connector API changed. Follow the Creating Connectors guide for more info on creating new connectors and converting Wagmi v1 connectors.

Removed individual entrypoints

Previously, each connector had its own entrypoint to optimize tree-shaking. Since all connectors now have package.json#sideEffects enabled, this is no longer necessary and the entrypoint is unified. Use the '@wagmi/connectors' package instead.

import { InjectedConnector } from '@wagmi/core/connectors/injected'
import { CoinbaseWalletConnector } from '@wagmi/core/connectors/coinbaseWallet'
import { coinbaseWallet, injected } from '@wagmi/connectors'

Removed `MetaMaskConnector`

The MetaMaskConnector was removed since it was nearly the same thing as the InjectedConnector. Use the injected connector instead, along with the target parameter set to 'metaMask', for the same behavior.

import { MetaMaskConnector } from '@wagmi/core/connectors/metaMask'
import { injected } from '@wagmi/connectors'

const connector = new MetaMaskConnector()
const connector = injected({ target: 'metaMask' })

Renamed connectors

In Wagmi v1, connectors were classes you needed to instantiate. In Wagmi v2, connectors are functions. As a result, the API has changed. Connectors have the following new names:

CoinbaseWalletConnector is now coinbaseWallet.
InjectedConnector is now injected.
SafeConnector is now safe.
WalletConnectConnector is now walletConnect.

To create a connector, you now call the connector function with parameters.

import { WalletConnectConnector } from '@wagmi/core/connectors/walletConnect'
import { walletConnect } from '@wagmi/connectors'

const connector = new WalletConnectConnector({ 
const connector = walletConnect({ 
  projectId: '3fcc6bba6f1de962d911bb5b5c3dba68',
})

Removed `WalletConnectLegacyConnector`

WalletConnect v1 was sunset June 28, 2023. Use the walletConnect connector instead.

import { WalletConnectLegacyConnector } from '@wagmi/core/connectors/walletConnectLegacy'
import { walletConnect } from '@wagmi/connectors'

const connector = new WalletConnectLegacyConnector({ 
const connector = walletConnect({ 
  projectId: '3fcc6bba6f1de962d911bb5b5c3dba68',
})

Chains

Updated `'@wagmi/core/chains'` entrypoint

Chains now live in the Viem repository. As a result, the '@wagmi/core/chains' entrypoint now proxies all chains from 'viem/chains' directly.

Removed `mainnet` and `sepolia` from main entrypoint

Since the '@wagmi/core/chains' entrypoint now proxies 'viem/chains', mainnet and sepolia were removed from the main entrypoint. Use the '@wagmi/core/chains' entrypoint instead.

import { mainnet, sepolia } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

Errors

A number of errors were renamed to better reflect their functionality or replaced by Viem errors.

Miscellaneous

Removed internal ENS normalization

Before v2, Wagmi handled ENS name normalization internally for getEnsAddress, getEnsAvatar, and getEnsResolver, using Viem's normalize function. This added extra bundle size as full normalization is quite heavy. For v2, you must normalize ENS names yourself before passing them to these actions. You can use Viem's normalize function or any other function that performs UTS-46 normalization.

index.tsconfig.ts

import { getEnsAddress } from '@wagmi/core'
import { normalize } from 'viem'
import { config } from './config'

const result = await getEnsAddress(config, {
  name: 'wevm.eth', 
  name: normalize('wevm.eth'), 
})

import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

export const config = createConfig({
  chains: [mainnet, sepolia],
  transports: {
    [mainnet.id]: http(),
    [sepolia.id]: http(),
  },
})

By inverting control, Wagmi lets you choose how much normalization to do. For example, maybe your project only allows ENS names that are numeric so no normalization is not needed. Check out the ENS documentation for more information on normalizing names.

Removed `configureChains`

The Wagmi v2 Config now has native multichain support using the chains parameter so the configureChains function is no longer required.

import { configureChains, createConfig } from '@wagmi/core'
import { http, createConfig } from '@wagmi/core'
import { mainnet, sepolia } from '@wagmi/core/chains'

const { chains, publicClient } = configureChains(
  [mainnet, sepolia],
  [publicProvider(), publicProvider()],
)

export const config = createConfig({
  publicClient, 
  chains: [mainnet, sepolia], 
  transports: { 
    [mainnet.id]: http(), 
    [sepolia.id]: http(), 
  }, 
})

Removed ABI exports

Import from Viem instead.

import { erc20ABI } from '@wagmi/core'
import { erc20Abi } from 'viem'

Removed `'@wagmi/core/providers/*` entrypoints

It never made sense that we would have provider URLs hardcoded in the Wagmi codebase. Use Viem transports along with RPC provider URLs instead.

import { alchemyProvider } from '@wagmi/core/providers/alchemy'
import { http } from 'viem'

const transport = http('https://mainnet.example.com')

Updated `createConfig` parameters

Removed autoConnect. The reconnecting behavior must be managed manually and is not related to the Wagmi Config. Use the reconnect action instead.
Removed publicClient and webSocketPublicClient. Use transports or client instead.
Removed logger. Wagmi no longer logs debug information to console.

Updated `Config` object

Removed config.connector. Use config.state.connections.get(config.state.current)?.connector instead.
Removed config.data. Use config.state.connections.get(config.state.current) instead.
Removed config.error. Was unused and not needed.
Removed config.lastUsedChainId. Use config.state.connections.get(config.state.current)?.chainId instead.
Removed config.publicClient. Use config.getClient() or getPublicClient instead.
Removed config.status. Use config.state.status instead.
Removed config.webSocketClient. Use config.getClient() or getPublicClient instead.
Removed config.clearState. Was unused and not needed.
Removed config.autoConnect(). Use reconnect action instead.
Renamed config.setConnectors. Use config._internal.setConnectors instead.
Removed config.setLastUsedConnector. Use config.storage?.setItem('recentConnectorId', connectorId) instead.
Removed getConfig. config should be passed explicitly to actions instead of using global config.

Deprecations

Deprecated `getBalance` `token` parameter

Moving forward, getBalance will only work for native currencies, thus the token parameter is no longer supported. Use readContracts instead.

import { getBalance } from '@wagmi/core'
import { readContracts } from '@wagmi/core'
import { erc20Abi } from 'viem'
import { config } from './config'

const result = await getBalance(config, { 
  address: '0x4557B18E779944BFE9d78A672452331C186a9f48', 
  token: '0x6B175474E89094C44Da98b954EedeAC495271d0F', 
})
const result = await readContracts(config, { 
  allowFailure: false, 
  contracts: [ 
    { 
      address: '0x6B175474E89094C44Da98b954EedeAC495271d0F', 
      abi: erc20Abi, 
      functionName: 'balanceOf', 
      args: ['0x4557B18E779944BFE9d78A672452331C186a9f48'], 
    }, 
    { 
      address: '0x6B175474E89094C44Da98b954EedeAC495271d0F', 
      abi: erc20Abi, 
      functionName: 'decimals', 
    }, 
    { 
      address: '0x6B175474E89094C44Da98b954EedeAC495271d0F', 
      abi: erc20Abi, 
      functionName: 'symbol', 
    }, 
  ] 
})

Deprecated `getBalance` `unit` parameter and `formatted` return value

Moving forward, getBalance will not accept the unit parameter or return a formatted value. Instead you can call formatUnits from Viem directly or use another number formatting library, like dnum instead.

import { formatUnits } from 'viem'
import { getBalance } from '@wagmi/core'

const result = await getBalance({
  address: '0x4557B18E779944BFE9d78A672452331C186a9f48',
  unit: 'ether', 
})
result.formatted
formatUnits(result.value, result.decimals)

Deprecated `getToken`

Moving forward, getToken is no longer supported. Use readContracts instead.

import { getToken } from '@wagmi/core'
import { readContracts } from '@wagmi/core'
import { erc20Abi } from 'viem'
import { config } from './config'

const result = await getToken(config, { 
  address: '0x6B175474E89094C44Da98b954EedeAC495271d0F', 
})
const result = await readContracts(config, { 
  allowFailure: false, 
  contracts: [ 
    { 
      address: '0x6B175474E89094C44Da98b954EedeAC495271d0F', 
      abi: erc20Abi, 
      functionName: 'decimals', 
    }, 
    { 
      address: '0x6B175474E89094C44Da98b954EedeAC495271d0F', 
      abi: erc20Abi, 
      functionName: 'name', 
    }, 
    { 
      address: '0x6B175474E89094C44Da98b954EedeAC495271d0F', 
      abi: erc20Abi, 
      functionName: 'symbol', 
    }, 
    { 
      address: '0x6B175474E89094C44Da98b954EedeAC495271d0F', 
      abi: erc20Abi, 
      functionName: 'totalSupply', 
    }, 
  ] 
})

Deprecated `formatUnits` parameters and return values

The formatUnits parameter and related return values (e.g. result.formatted) are deprecated for the following actions:

Instead you can call formatUnits from Viem directly or use another number formatting library, like dnum instead.

import { formatUnits } from 'viem'
import { getToken } from '@wagmi/core'

const result = await getToken({
  address: '0x6B175474E89094C44Da98b954EedeAC495271d0F',
  formatUnits: 'ether',
})
result.totalSupply.formatted
formatUnits(result.totalSupply.value, 18)

This allows us to invert control to users so they can handle number formatting however they want, taking into account precision, localization, and more.

Renamed actions

The following actions were renamed to better reflect their functionality and underlying Viem actions:

fetchBalance is now getBalance
fetchBlockNumber is now getBlockNumber
fetchEnsAddress is now getEnsAddress
fetchEnsAvatar is now getEnsAvatar
fetchEnsName is now getEnsName
fetchEnsResolver is now getEnsResolver
fetchToken is now getToken
fetchTransaction is now getTransaction
switchNetwork is now switchChain
waitForTransaction is now waitForTransactionReceipt

Migrate from v1 to v2 ​

Dependencies ​

Dropped CommonJS support ​

Actions ​

Removed config singleton ​

Removed getContract ​

Removed getNetwork and watchNetwork ​

Removed getWebSocketPublicClient and watchWebSocketPublicClient ​

Removed watchReadContract, watchReadContracts, and watchReadMulticall ​

Removed fetchFeeData ​

Removed prepareWriteContract ​

Removed prepareSendTransaction ​

Updated sendTransaction and writeContract return type ​

Updated connect return type ​

Renamed parameters and return types ​

Connectors ​

Moved Wagmi Connectors to peer dependencies ​

Updated connector API ​

Removed individual entrypoints ​

Removed MetaMaskConnector ​

Renamed connectors ​

Removed WalletConnectLegacyConnector ​

Chains ​

Updated '@wagmi/core/chains' entrypoint ​

Removed mainnet and sepolia from main entrypoint ​

Errors ​

Miscellaneous ​

Removed internal ENS normalization ​

Removed configureChains ​

Removed ABI exports ​

Removed '@wagmi/core/providers/* entrypoints ​

Updated createConfig parameters ​

Updated Config object ​

Deprecations ​

Deprecated getBalance token parameter ​

Deprecated getBalance unit parameter and formatted return value ​

Deprecated getToken ​

Deprecated formatUnits parameters and return values ​

Renamed actions ​

Migrate from v1 to v2

Dependencies

Dropped CommonJS support

Actions

Removed `config` singleton

Removed `getContract`

Removed `getNetwork` and `watchNetwork`

Removed `getWebSocketPublicClient` and `watchWebSocketPublicClient`

Removed `watchReadContract`, `watchReadContracts`, and `watchReadMulticall`

Removed `fetchFeeData`

Removed `prepareWriteContract`

Removed `prepareSendTransaction`

Updated `sendTransaction` and `writeContract` return type

Updated `connect` return type

Renamed parameters and return types

Connectors

Moved Wagmi Connectors to peer dependencies

Updated connector API

Removed individual entrypoints

Removed `MetaMaskConnector`

Renamed connectors

Removed `WalletConnectLegacyConnector`

Chains

Updated `'@wagmi/core/chains'` entrypoint

Removed `mainnet` and `sepolia` from main entrypoint

Errors

Miscellaneous

Removed internal ENS normalization

Removed `configureChains`

Removed ABI exports

Removed `'@wagmi/core/providers/*` entrypoints

Updated `createConfig` parameters

Updated `Config` object

Deprecations

Deprecated `getBalance` `token` parameter

Deprecated `getBalance` `unit` parameter and `formatted` return value

Deprecated `getToken`

Deprecated `formatUnits` parameters and return values

Renamed actions