Configure the BlackSwan JavaScript Client and Contracts - BlackSwan

After installing the SDK, you configure a BlackSwanClient instance by passing your target network and RPC endpoint. The client handles all contract interactions and data formatting, so you can focus on building your application.

Constructor parameters

Pass a configuration object to BlackSwanClient with the following properties:

Parameter	Type	Required	Description
network	string	Yes	Target network: `"amoy"` or `"sepolia"`
rpcUrl	string	Yes	Your RPC endpoint URL

Initialize the client

import { BlackSwanClient } from "blackswan-sdk";

// Polygon Amoy (recommended for testing)
const client = new BlackSwanClient({
  network: "amoy",
  rpcUrl: process.env.NEXT_PUBLIC_RPC_URL
});

// Ethereum Sepolia
const client = new BlackSwanClient({
  network: "sepolia",
  rpcUrl: process.env.NEXT_PUBLIC_RPC_URL
});

Contract addresses

BlackSwan contract addresses are available as named exports from blackswan-sdk. Import the constants for your target network instead of hardcoding addresses in your application.

import { AMOY_CONTRACTS, SEPOLIA_CONTRACTS } from "blackswan-sdk";

// Amoy
AMOY_CONTRACTS.P2PLENDING    // 0x7E04C0a283d372537E547086D37642776199C1DC
AMOY_CONTRACTS.BLACKSWANSBT  // 0x6665e5E15Ee295d9de05C6D57c629F33653687D7

// Sepolia
SEPOLIA_CONTRACTS.P2PLENDING   // 0x20D2E08E283FF4052B2B02A3475dda1B320cD26f
SEPOLIA_CONTRACTS.BLACKSWANSBT // 0xf8D2F43227Ea25a7fD0B34E1b74FF6FF2722879F

Store your RPC URL in an environment variable (e.g. NEXT_PUBLIC_RPC_URL for Next.js, or RPC_URL for Node.js) rather than committing it directly in source code. This keeps your credentials out of version control and makes it easy to swap providers without touching your application logic.