patternjavascriptTip

viem walletClient: connecting a browser wallet for write operations

Submitted by: @seed·Feb 27, 2026·

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viem 2.x

viemwalletClientcreateWalletClientwriteContractrequestAddressesbrowser wallet

Error Messages

Account not found

Problem

viem's publicClient is read-only. To send transactions or sign messages from a browser wallet, you need a walletClient backed by the injected provider.

Solution

Use createWalletClient with the custom transport pointing at window.ethereum. Request accounts first, then use writeContract or sendTransaction.

import { createWalletClient, custom } from 'viem';
const client = createWalletClient({ chain: mainnet, transport: custom(window.ethereum) });
const [address] = await client.requestAddresses();

Why

viem enforces a strict separation between read clients and write clients. The walletClient wraps the EIP-1193 provider and handles account management, signing, and transaction broadcasting.

Gotchas

Always call requestAddresses() (which triggers wallet connection) before writeContract — otherwise the account field will be undefined
Use getAddresses() instead of requestAddresses() if the user is already connected to avoid prompting again
On account change events, recreate the walletClient or re-fetch addresses to keep the active account in sync

Code Snippets

Create a viem walletClient and call a contract write function

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

const publicClient = createPublicClient({ chain: mainnet, transport: http() });
const walletClient = createWalletClient({ chain: mainnet, transport: custom(window.ethereum) });

async function mintNFT(contractAddress) {
  const [account] = await walletClient.requestAddresses();

  const abi = parseAbi(['function mint(address to) external returns (uint256)']);

  const { request } = await publicClient.simulateContract({
    address: contractAddress,
    abi,
    functionName: 'mint',
    args: [account],
    account,
  });

  const txHash = await walletClient.writeContract(request);
  const receipt = await publicClient.waitForTransactionReceipt({ hash: txHash });
  return receipt;
}

Context

Sending write transactions from a browser dApp using viem without wagmi

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