Client Setup

This page covers the core SDK lifecycle:

Create config (createCofheConfig)
Create client (createCofheClient)
Connect (client.connect)
Manage connection (change account / disconnect)

1. Create config

Import createCofheConfig from the entrypoint that matches your runtime:

Browser apps: @cofhe/sdk/web
Node.js scripts/backends: @cofhe/sdk/node

The only required field is supportedChains.

import { createCofheConfig } from '@cofhe/sdk/web';
import { chains } from '@cofhe/sdk/chains';

const config = createCofheConfig({
  supportedChains: [chains.sepolia],

  // Optional knobs
  // defaultACPExpiration: 60 * 60 * 24 * 30,
  // useWorkers: true,
});

2. Create the client

import { createCofheConfig, createCofheClient } from '@cofhe/sdk/web';
import { chains } from '@cofhe/sdk/chains';

const config = createCofheConfig({ supportedChains: [chains.sepolia] });
const cofheClient = createCofheClient(config);

cofheClient.connected; // false
cofheClient.connecting; // false

3. Connect

The SDK connects to CoFHE using viem clients:

PublicClient: read-only chain access
WalletClient: signing + sending transactions

The wallet client must carry an account. connect reads the connected address from walletClient.account, and falls back to eth_accounts on the transport. A wallet client created with http() and no account has neither, so connect throws PublicWalletGetAddressesFailed and the client stays disconnected. In the browser, take the account from the injected wallet. In Node.js, build it from a private key.

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

const [account] = await window.ethereum.request({
  method: 'eth_requestAccounts',
});

const publicClient = createPublicClient({
  chain: sepolia,
  transport: http(),
});

const walletClient = createWalletClient({
  chain: sepolia,
  transport: custom(window.ethereum),
  account,
});

await cofheClient.connect(publicClient, walletClient);

cofheClient.connected; // true
cofheClient.connection.account; // the address selected in the wallet

import { createPublicClient, createWalletClient, http } from 'viem';
import { sepolia } from 'viem/chains';
import { privateKeyToAccount } from 'viem/accounts';

const account = privateKeyToAccount('0xYOUR_PRIVATE_KEY');

const publicClient = createPublicClient({
  chain: sepolia,
  transport: http(),
});

const walletClient = createWalletClient({
  chain: sepolia,
  transport: http(),
  account,
});

await cofheClient.connect(publicClient, walletClient);

cofheClient.connected; // true
cofheClient.connection.account; // account.address

Using adapters

If you use Ethers, @cofhe/sdk/adapters converts an Ethers provider and signer into viem-shaped clients, and derives the account from the signer. wagmi already gives you viem clients, so pass them to connect directly. The wallet client from useWalletClient carries the connected account.

import { Ethers6Adapter } from '@cofhe/sdk/adapters';
import { ethers } from 'ethers';

const provider = new ethers.JsonRpcProvider('https://rpc.sepolia.org');
const signer = new ethers.Wallet('0xYOUR_PRIVATE_KEY', provider);

const { publicClient, walletClient } = await Ethers6Adapter(
  provider,
  signer
);

await cofheClient.connect(publicClient, walletClient);

import { Ethers5Adapter } from '@cofhe/sdk/adapters';
import { ethers } from 'ethers5';

const provider = new ethers.providers.JsonRpcProvider(
  'https://rpc.sepolia.org'
);
const signer = new ethers.Wallet('0xYOUR_PRIVATE_KEY').connect(provider);

const { publicClient, walletClient } = await Ethers5Adapter(
  provider,
  signer
);

await cofheClient.connect(publicClient, walletClient);

import { useEffect } from 'react';
import { usePublicClient, useWalletClient } from 'wagmi';

function useConnectCofhe() {
  const publicClient = usePublicClient();
  const { data: walletClient } = useWalletClient();

  useEffect(() => {
    // useWalletClient resolves only after the user connects a wallet
    if (!publicClient || !walletClient) return;
    cofheClient.connect(publicClient, walletClient);
  }, [publicClient, walletClient]);
}

4. Managing connections

Reconnect behavior

Calling connect again with the same clients is a no-op. Calling it with new clients replaces the connection state.

Changing connected account

To switch the client’s connected account, call cofheClient.connect() with a wallet client that carries the new account.

import { privateKeyToAccount } from 'viem/accounts';

const bob = privateKeyToAccount('0xBOB_PRIVATE_KEY');
const alice = privateKeyToAccount('0xALICE_PRIVATE_KEY');

const bobWalletClient = createWalletClient({
  chain: sepolia,
  transport: http(),
  account: bob,
});
const aliceWalletClient = createWalletClient({
  chain: sepolia,
  transport: http(),
  account: alice,
});

// Connect as Bob
await cofheClient.connect(publicClient, bobWalletClient);
cofheClient.connection.account; // bob.address

// Switch to Alice
await cofheClient.connect(publicClient, aliceWalletClient);
cofheClient.connection.account; // alice.address

Disconnecting

To manually disconnect, call cofheClient.disconnect(). This clears the in-memory connection state (clients/account/chainId) and marks the client as disconnected. It does not delete persisted ACPs or stored FHE keys.

cofheClient.disconnect();
cofheClient.connected; // false

Introduction

Quick Start

Guides

Hardhat Plugin

Foundry Plugin

Examples

Reference

1. Create config

2. Create the client

3. Connect

Using adapters

4. Managing connections

Reconnect behavior

Changing connected account

Disconnecting

​1. Create config

​2. Create the client

​3. Connect

​Using adapters

​4. Managing connections

​Reconnect behavior

​Changing connected account

​Disconnecting

1. Create config

2. Create the client

3. Connect

Using adapters

4. Managing connections

Reconnect behavior

Changing connected account

Disconnecting