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eth_blockNumber

Returns the number of the most recent block on Arbitrum Layer 2.

When to Use This Method​

eth_blockNumber is fundamental for:

  • Syncing Applications - Keep your dApp in sync with the latest blockchain state
  • Transaction Monitoring - Verify confirmations by comparing block numbers
  • Event Filtering - Set the correct block range for querying logs
  • Health Checks - Monitor node connectivity and sync status

Parameters​

This method accepts no parameters.

{
  "jsonrpc": "2.0",
  "method": "eth_blockNumber",
  "params": [],
  "id": 1
}

Returns​

QUANTITY - Integer of the current block number the node is synced to.

  • Type: Hexadecimal string
  • Format: 0x prefixed
  • Example: 0x5bad55 (6008149 in decimal)

Implementation Examples​

curl -X POST https://api-arbitrum-mainnet-archive.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_blockNumber",
    "params": [],
    "id": 1
  }'

Response Example​

Successful Response​

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x5bad55"
}

Error Response​

{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32603,
    "message": "Internal error"
  }
}

Common Use Cases​

1. Block Confirmation Counter​

Monitor transaction confirmations:

async function getConfirmations(txHash) {
  const tx = await provider.getTransaction(txHash);
  if (!tx || !tx.blockNumber) return 0;
  
  const currentBlock = await provider.getBlockNumber();
  return currentBlock - tx.blockNumber + 1;
}

// Wait for specific confirmations
async function waitForConfirmations(txHash, confirmations = 6) {
  let currentConfirmations = 0;
  
  while (currentConfirmations < confirmations) {
    currentConfirmations = await getConfirmations(txHash);
    console.log(`Confirmations: ${currentConfirmations}/${confirmations}`);
    await new Promise(r => setTimeout(r, 2000)); // Check every 2 seconds
  }
  
  return true;
}

2. Event Log Filtering​

Query events from recent blocks:

async function getRecentEvents(contract, eventName, blockRange = 100) {
  const currentBlock = await provider.getBlockNumber();
  const fromBlock = currentBlock - blockRange;
  
  const filter = contract.filters[eventName]();
  const events = await contract.queryFilter(filter, fromBlock, currentBlock);
  
  return events;
}

3. Node Health Monitoring​

Check if your node is synced:

async function checkNodeHealth() {
  try {
    const blockNumber = await provider.getBlockNumber();
    const block = await provider.getBlock(blockNumber);
    
    const now = Date.now() / 1000;
    const blockAge = now - block.timestamp;
    
    if (blockAge > 60) {
      console.warn(`Node may be behind. Last block was ${blockAge}s ago`);
      return false;
    }
    
    console.log(`Node healthy. Latest block: ${blockNumber}`);
    return true;
  } catch (error) {
    console.error('Node unreachable:', error);
    return false;
  }
}

Performance Optimization​

Caching Strategy​

Cache block numbers to reduce API calls:

class BlockNumberCache {
  constructor(ttl = 2000) { // 2 second cache
    this.cache = null;
    this.timestamp = 0;
    this.ttl = ttl;
  }
  
  async get(provider) {
    const now = Date.now();
    
    if (this.cache && (now - this.timestamp) < this.ttl) {
      return this.cache;
    }
    
    this.cache = await provider.getBlockNumber();
    this.timestamp = now;
    return this.cache;
  }
  
  invalidate() {
    this.cache = null;
    this.timestamp = 0;
  }
}

const blockCache = new BlockNumberCache();

Batch Requests​

Combine with other calls for efficiency:

const batch = [
  { jsonrpc: '2.0', method: 'eth_blockNumber', params: [], id: 1 },
  { jsonrpc: '2.0', method: 'eth_gasPrice', params: [], id: 2 },
  { jsonrpc: '2.0', method: 'eth_chainId', params: [], id: 3 }
];

const response = await fetch('https://api-arbitrum-mainnet-archive.n.dwellir.com/YOUR_API_KEY', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify(batch)
});

const results = await response.json();

Error Handling​

Common errors and solutions:

Error CodeDescriptionSolution
-32603Internal errorRetry with exponential backoff
-32005Rate limit exceededImplement rate limiting client-side
-32000Execution revertedCheck node sync status
async function safeGetBlockNumber(maxRetries = 3) {
  for (let i = 0; i < maxRetries; i++) {
    try {
      return await provider.getBlockNumber();
    } catch (error) {
      if (error.code === -32005) {
        // Rate limited, wait exponentially
        await new Promise(r => setTimeout(r, Math.pow(2, i) * 1000));
      } else if (i === maxRetries - 1) {
        throw error;
      }
    }
  }
}