Client Setup

Configure and connect the @cofhe/sdk client with viem, Ethers, or wagmi

This page covers the core SDK lifecycle:

1. Create config (createCofheConfig)
2. Create client (createCofheClient)
3. Connect (client.connect)
4. 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
  // defaultPermitExpiration: 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

If you already have viem clients, pass them directly.

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

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

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

await cofheClient.connect(publicClient, walletClient);

cofheClient.connected; // true

Using adapters

If you use a different wallet/provider stack, @cofhe/sdk/adapters provides adapters that convert into viem-shaped clients.

Ethers v6

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 { WagmiAdapter } from '@cofhe/sdk/adapters';
import { createPublicClient, createWalletClient, http } from 'viem';
import { sepolia } from 'viem/chains';

const wagmiPublicClient = createPublicClient({
  chain: sepolia,
  transport: http(),
});
const wagmiWalletClient = createWalletClient({
  chain: sepolia,
  transport: http(),
});

const { publicClient, walletClient } = await WagmiAdapter(
  wagmiWalletClient,
  wagmiPublicClient
);

await cofheClient.connect(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 updated viem clients.

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

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

// Switch to Alice
await cofheClient.connect(publicClient, aliceWalletClient);
cofheClient.connection.account; // Alice's 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 permits or stored FHE keys.

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