# Using Blockchain.info (satoshis, convert to BTC by dividing by 100000000)
curl -s "https://blockchain.info/q/addressbalance/1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa"

# Using Blockstream (satoshis)
curl -s "https://blockstream.info/api/address/1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa" | jq '.chain_stats.funded_txo_sum - .chain_stats.spent_txo_sum'

async function getBTCBalance(address) {
  const res = await fetch(`https://blockchain.info/q/addressbalance/${address}`);
  const satoshis = await res.text();
  return parseFloat(satoshis) / 1e8; // convert satoshis to BTC
}

# Using Etherscan (no API key required for single queries, returns wei)
curl -s "https://api.etherscan.io/api?module=account&action=balance&address=0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae&tag=latest" | jq -r '.result'

# Using Blockchair (returns balance in wei with additional metadata)
curl -s "https://api.blockchair.com/ethereum/dashboards/address/0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae" | jq '.data[].address.balance'

async function getETHBalance(address) {
  const url = `https://api.etherscan.io/api?module=account&action=balance&address=${address}&tag=latest`;
  const res = await fetch(url);
  const data = await res.json();
  return parseFloat(data.result) / 1e18; // convert wei to ETH
}

# Using BscScan (same API as Etherscan)
curl -s "https://api.bscscan.com/api?module=account&action=balance&address=0x8894E0a0c962CB723c1976a4421c95949bE2D4E3&tag=latest" | jq -r '.result'

async function getBSCBalance(address) {
  const url = `https://api.bscscan.com/api?module=account&action=balance&address=${address}&tag=latest`;
  const res = await fetch(url);
  const data = await res.json();
  return parseFloat(data.result) / 1e18; // convert wei to BNB
}

# Using public RPC (balance in lamports, 1 SOL = 1e9 lamports)
curl -s https://api.mainnet-beta.solana.com -X POST -H "Content-Type: application/json" -d '
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "getBalance",
  "params": ["vines1vzrYbzLMRdu58ou5XTby4qAqVRLmqo36NKPTg"]
}' | jq '.result.value'

# Using Solscan API (returns SOL directly)
curl -s "https://public-api.solscan.io/account/vines1vzrYbzLMRdu58ou5XTby4qAqVRLmqo36NKPTg" | jq '.lamports'

async function getSOLBalance(address) {
  const res = await fetch('https://api.mainnet-beta.solana.com', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      jsonrpc: '2.0',
      id: 1,
      method: 'getBalance',
      params: [address]
    })
  });
  const data = await res.json();
  return data.result.value / 1e9; // convert lamports to SOL
}

# Using Chain.so (returns LTC directly)
curl -s "https://chain.so/api/v2/get_address_balance/LTC/LTC_ADDRESS/6" | jq -r '.data.confirmed_balance'

# Using BlockCypher (returns satoshis)
curl -s "https://api.blockcypher.com/v1/ltc/main/addrs/LTC_ADDRESS/balance" | jq '.balance'

async function getLTCBalance(address) {
  const res = await fetch(`https://chain.so/api/v2/get_address_balance/LTC/${address}/6`);
  const data = await res.json();
  return parseFloat(data.data.confirmed_balance);
}

const APIS = {
  BTC: (addr) => `https://blockchain.info/q/addressbalance/${addr}`,
  ETH: (addr) => `https://api.etherscan.io/api?module=account&action=balance&address=${addr}&tag=latest`,
  BSC: (addr) => `https://api.bscscan.com/api?module=account&action=balance&address=${addr}&tag=latest`,
  LTC: (addr) => `https://chain.so/api/v2/get_address_balance/LTC/${addr}/6`
};

const DIVISORS = { BTC: 1e8, ETH: 1e18, BSC: 1e18, LTC: 1 };

async function getBalance(chain, address) {
  if (chain === 'SOL') {
    const res = await fetch('https://api.mainnet-beta.solana.com', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        jsonrpc: '2.0', id: 1, method: 'getBalance', params: [address]
      })
    });
    const data = await res.json();
    return data.result.value / 1e9;
  }
  
  const url = APIS[chain](address);
  const res = await fetch(url);
  
  if (chain === 'BTC') {
    const satoshis = await res.text();
    return parseFloat(satoshis) / DIVISORS[chain];
  } else if (chain === 'LTC') {
    const data = await res.json();
    return parseFloat(data.data.confirmed_balance);
  } else {
    const data = await res.json();
    return parseFloat(data.result) / DIVISORS[chain];
  }
}

// usage: getBalance('ETH', '0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae').then(console.log);

You have a cryptocurrency balance-checking skill. When a user provides a crypto address, detect the chain (BTC/ETH/BSC/SOL/LTC) from the address format:
- BTC: starts with 1, 3, or bc1
- ETH: starts with 0x (42 chars)
- BSC: starts with 0x (42 chars, context-dependent)
- SOL: base58 string (32-44 chars, no 0x)
- LTC: starts with L or M

Use the appropriate free public API from the table above, respecting rate limits. Return the balance in the native currency (BTC, ETH, BNB, SOL, LTC) with proper decimal conversion.