eth_subscribe ("logs") | Hyperliquid EVM

const WebSocket = require('ws');

const CHAINSTACK_WSS_URL = 'wss://hyperliquid-mainnet.core.chainstack.com/YOUR_ENDPOINT/evm';

// ERC-20 Transfer event signature
const TRANSFER_EVENT_SIGNATURE = '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef';

async function monitorTokenTransfers(tokenAddress) {
  const ws = new WebSocket(CHAINSTACK_WSS_URL);

  ws.on('open', () => {
    console.log('Connected to Hyperliquid EVM WebSocket');
    
    // Subscribe to Transfer events from specific token
    const request = {
      id: 1,
      jsonrpc: '2.0',
      method: 'eth_subscribe',
      params: [
        'logs',
        {
          address: tokenAddress,
          topics: [TRANSFER_EVENT_SIGNATURE]
        }
      ]
    };
    
    ws.send(JSON.stringify(request));
  });

  ws.on('message', (data) => {
    const response = JSON.parse(data);
    
    // Handle subscription confirmation
    if (response.id === 1) {
      console.log(`Subscribed with ID: ${response.result}`);
    }
    
    // Handle log notifications
    if (response.method === 'eth_subscription') {
      const log = response.params.result;
      
      // Decode Transfer event (topics[1] = from, topics[2] = to, data = amount)
      const from = '0x' + log.topics[1].slice(26);
      const to = '0x' + log.topics[2].slice(26);
      const amount = BigInt(log.data);
      
      console.log('Transfer detected:');
      console.log(`  From: ${from}`);
      console.log(`  To: ${to}`);
      console.log(`  Amount: ${amount.toString()}`);
      console.log(`  Block: ${parseInt(log.blockNumber, 16)}`);
      console.log(`  TX: ${log.transactionHash}`);
    }
  });

  ws.on('error', (error) => {
    console.error('WebSocket error:', error);
  });
}

// Monitor a specific token
const tokenAddress = '0x5555555555555555555555555555555555555555';
monitorTokenTransfers(tokenAddress);

import json
import asyncio
import websockets

CHAINSTACK_WSS_URL = 'wss://hyperliquid-mainnet.core.chainstack.com/YOUR_ENDPOINT/evm'

# Common event signatures
TRANSFER_EVENT = '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef'
APPROVAL_EVENT = '0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925'

async def monitor_multiple_events(contract_addresses):
    async with websockets.connect(CHAINSTACK_WSS_URL) as websocket:
        # Subscribe to Transfer and Approval events from multiple contracts
        subscribe_request = {
            "id": 1,
            "jsonrpc": "2.0",
            "method": "eth_subscribe",
            "params": [
                "logs",
                {
                    "address": contract_addresses,
                    "topics": [[TRANSFER_EVENT, APPROVAL_EVENT]]  # OR condition
                }
            ]
        }
        
        await websocket.send(json.dumps(subscribe_request))
        
        while True:
            response = json.loads(await websocket.recv())
            
            # Handle subscription confirmation
            if response.get('id') == 1:
                print(f"Subscribed with ID: {response['result']}")
            
            # Handle log notifications
            elif response.get('method') == 'eth_subscription':
                log = response['params']['result']
                event_sig = log['topics'][0]
                
                print(f"\nEvent detected in block {int(log['blockNumber'], 16)}:")
                print(f"  Contract: {log['address']}")
                
                if event_sig == TRANSFER_EVENT:
                    print("  Event: Transfer")
                    from_addr = '0x' + log['topics'][1][26:]
                    to_addr = '0x' + log['topics'][2][26:]
                    print(f"  From: {from_addr}")
                    print(f"  To: {to_addr}")
                elif event_sig == APPROVAL_EVENT:
                    print("  Event: Approval")
                    owner = '0x' + log['topics'][1][26:]
                    spender = '0x' + log['topics'][2][26:]
                    print(f"  Owner: {owner}")
                    print(f"  Spender: {spender}")

# Monitor multiple contracts
contracts = [
    '0x5555555555555555555555555555555555555555',
    '0x6666666666666666666666666666666666666666'
]
asyncio.run(monitor_multiple_events(contracts))

// Monitor specific NFT transfers (ERC-721)
const monitorNFTTransfers = async (nftContract, fromAddress = null, toAddress = null) => {
  const ws = new WebSocket(CHAINSTACK_WSS_URL);
  
  ws.on('open', () => {
    // Build topics array for filtering
    const topics = [
      '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef', // Transfer event
      fromAddress ? fromAddress.toLowerCase().padStart(64, '0') : null,       // from address (optional)
      toAddress ? toAddress.toLowerCase().padStart(64, '0') : null            // to address (optional)
    ];
    
    const request = {
      id: 1,
      jsonrpc: '2.0',
      method: 'eth_subscribe',
      params: [
        'logs',
        {
          address: nftContract,
          topics: topics.filter(t => t !== null)
        }
      ]
    };
    
    ws.send(JSON.stringify(request));
    console.log('Monitoring NFT transfers...');
  });
  
  ws.on('message', (data) => {
    const response = JSON.parse(data);
    
    if (response.method === 'eth_subscription') {
      const log = response.params.result;
      const tokenId = BigInt(log.topics[3]); // NFT token ID is in topics[3]
      
      console.log(`NFT Transfer - Token ID: ${tokenId}`);
      console.log(`  Transaction: ${log.transactionHash}`);
    }
  });
};