Alchemy Install & Auth

Overview

Install the alchemy-sdk npm package and configure API authentication. Alchemy provides blockchain infrastructure (RPC nodes, Enhanced APIs, NFT APIs, webhooks) across Ethereum, Polygon, Arbitrum, Optimism, Base, and Solana.

Prerequisites

• Node.js 18+ (or Python 3.10+ for alchemy-sdk Python)
• Free Alchemy account at alchemy.com
• API key from Alchemy Dashboard

Instructions

Step 1: Install the Alchemy SDK

# JavaScript/TypeScript (official SDK)
npm install alchemy-sdk

# Python (community SDK)
pip install alchemy-sdk

Step 2: Create an Alchemy App

1. Go to dashboard.alchemy.com
2. Click "Create new app"
3. Select chain: Ethereum, Polygon, Arbitrum, Optimism, Base, or Solana
4. Select network: Mainnet, Sepolia (testnet), or Mumbai
5. Copy the API key

Step 3: Configure Environment

# Set environment variable
export ALCHEMY_API_KEY="your-api-key-here"

# Or create .env file
cat > .env << 'EOF'
ALCHEMY_API_KEY=your-api-key-here
ALCHEMY_NETWORK=ETH_MAINNET
EOF

echo ".env" >> .gitignore

Step 4: Initialize and Verify

// src/alchemy-client.ts
import { Alchemy, Network } from 'alchemy-sdk';

const alchemy = new Alchemy({
  apiKey: process.env.ALCHEMY_API_KEY,
  network: Network.ETH_MAINNET,
});

// Verify connection
async function verifyConnection() {
  const blockNumber = await alchemy.core.getBlockNumber();
  console.log(`Connected! Latest block: ${blockNumber}`);
  return blockNumber;
}

verifyConnection().catch(console.error);

Step 5: Multi-Chain Configuration

// src/config/chains.ts
import { Alchemy, Network } from 'alchemy-sdk';

// Create clients for multiple chains
const chains = {
  ethereum: new Alchemy({ apiKey: process.env.ALCHEMY_API_KEY, network: Network.ETH_MAINNET }),
  polygon: new Alchemy({ apiKey: process.env.ALCHEMY_API_KEY, network: Network.MATIC_MAINNET }),
  arbitrum: new Alchemy({ apiKey: process.env.ALCHEMY_API_KEY, network: Network.ARB_MAINNET }),
  optimism: new Alchemy({ apiKey: process.env.ALCHEMY_API_KEY, network: Network.OPT_MAINNET }),
  base: new Alchemy({ apiKey: process.env.ALCHEMY_API_KEY, network: Network.BASE_MAINNET }),
};

export default chains;