Nexus SDK Setup

Install dependency

• Install the SDK package:

• npm install @avail-project/nexus-core

• or pnpm add @avail-project/nexus-core

• or yarn add @avail-project/nexus-core

Obtain an EIP-1193 provider

• Use any wallet connection stack to get a provider.

• Ensure the provider has a request method.

• Use a browser fallback only when appropriate:

• const provider = (window as any).ethereum

Construct the SDK instance

• Create new NexusSDK({ network, debug, siweChain }) .

• Provide network :

• 'mainnet' or 'testnet' to use default endpoints.

• NetworkConfig to use custom endpoints.

• Provide debug?: boolean to enable verbose SDK logging.

• Provide siweChain?: number to set the SIWE chain id (if you use SIWE).

Initialize once

• Create a single instance and reuse it.

• Store the instance in a module singleton or a React ref.

• Guard with sdk.isInitialized() to avoid re-init.

Minimal example

import { NexusSDK, type EthereumProvider } from '@avail-project/nexus-core';

const sdk = new NexusSDK({ network: 'mainnet' });

export async function initNexus(provider: EthereumProvider) { if (sdk.isInitialized()) return sdk; if (!provider || typeof provider.request !== 'function') { throw new Error('Invalid EIP-1193 provider'); } await sdk.initialize(provider); return sdk; }

Initialize when a wallet kit is already integrated (FamilyKit / wagmi-based)

• If your kit exposes a wagmi connector, derive an EIP-1193 provider from it.

• Use the same pattern as Nexus Elements: prefer connector.getProvider() on desktop and a walletClient.request wrapper on mobile.

• Example (adapt to your hooks and UI state):

import { NexusSDK, type EthereumProvider } from '@avail-project/nexus-core'; import { useAccount, useConnectorClient } from 'wagmi';

const sdk = new NexusSDK({ network: 'mainnet', debug: false });

async function initFromWalletKit(isMobile: boolean) { const { connector } = useAccount(); const { data: walletClient } = useConnectorClient();

const mobileProvider = walletClient && ({ request: (args: unknown) => walletClient.request(args as never), } as EthereumProvider);

const desktopProvider = await connector?.getProvider(); const effectiveProvider = isMobile ? mobileProvider : desktopProvider;

if (!effectiveProvider || typeof effectiveProvider.request !== 'function') { throw new Error('Invalid EIP-1193 provider from wallet kit'); }

if (!sdk.isInitialized()) { await sdk.initialize(effectiveProvider); }

return sdk; }

Handle disconnect / teardown

• On wallet disconnect, call await sdk.deinit() .

• Clear state (balances, hook refs, cached intents).

Use provider-only mode (optional)

• If you need balances before full init, call:

• await sdk.setEVMProvider(provider)

• Check sdk.hasEvmProvider to confirm.

Handle SSR / client-only execution

• Initialize in client-only code (useEffect or dynamic import) to avoid SSR issues.

Handle account changes

• If provider supports events, re-fetch balances on accountsChanged .

• If provider lacks .on /.removeListener , call:

• sdk.triggerAccountChange() after the wallet address changes.

Handle init errors

• Wrap sdk.initialize in try/catch.

• If SDK_INIT_STATE_NOT_EXPECTED , call await sdk.deinit() and retry.

• If WALLET_NOT_CONNECTED or CONNECT_ACCOUNT_FAILED , prompt user to reconnect.