Docs

eth_coinbase - Moonbeam RPC Method

Check the legacy eth_coinbase compatibility method on Moonbeam. Public endpoints may return an address, `unimplemented`, or another unsupported-method response depending on the client.

Checks the legacy eth_coinbase compatibility method on Moonbeam. Public endpoints may return an address, unimplemented, or another unsupported-method response depending on the client behind the endpoint.

Why Moonbeam? Build on the cross-chain connected EVM platform on Polkadot with $65M+ TVL and 100+ projects with full EVM compatibility on Polkadot, native XCM cross-chain messaging, 10K+ TPS, 24% staking APR, and $0.015 transaction costs.

Note: Treat eth_coinbase as a legacy compatibility probe. On shared infrastructure, this method may return unimplemented or another unsupported-method error, so it is not a dependable production signal.

When to Use This Method

eth_coinbase is relevant for cross-chain dApp developers, Polkadot builders, and teams requiring multi-chain interoperability when you need to:

  • Check client compatibility — Confirm whether the connected client still exposes eth_coinbase
  • Audit migration assumptions — Remove Ethereum-era assumptions that every endpoint reports an etherbase address
  • Harden integrations — Fall back to supported identity or chain-status methods when eth_coinbase is unavailable

Code Examples

Common Use Cases

1. Validator Configuration Verification

Verify that a node's coinbase matches the expected reward address:

JavaScript
async function verifyCoinbase(provider, expectedAddress) {
  try {
    const coinbase = await provider.send('eth_coinbase', []);

    if (coinbase.toLowerCase() === expectedAddress.toLowerCase()) {
      console.log('Coinbase address verified');
      return true;
    } else {
      console.warn(`Coinbase mismatch: expected ${expectedAddress}, got ${coinbase}`);
      return false;
    }
  } catch {
    console.error('Could not retrieve coinbase — may not be configured');
    return false;
  }
}

2. Block Producer Identification

Identify the coinbase address alongside block production details:

JavaScript
async function getProducerInfo(provider) {
  const [coinbase, mining, hashrate] = await Promise.allSettled([
    provider.send('eth_coinbase', []),
    provider.send('eth_mining', []),
    provider.send('eth_hashrate', [])
  ]);

  return {
    coinbase: coinbase.status === 'fulfilled' ? coinbase.value : 'not configured',
    isMining: mining.status === 'fulfilled' ? mining.value : false,
    hashrate: hashrate.status === 'fulfilled' ? parseInt(hashrate.value, 16) : 0
  };
}

3. Multi-Node Coinbase Audit

Audit coinbase addresses across a fleet of Moonbeam nodes:

JavaScript
async function auditCoinbases(endpoints) {
  const results = await Promise.all(
    endpoints.map(async (endpoint) => {
      const provider = new JsonRpcProvider(endpoint);
      try {
        const coinbase = await provider.send('eth_coinbase', []);
        return { endpoint, coinbase, configured: true };
      } catch {
        return { endpoint, coinbase: null, configured: false };
      }
    })
  );

  const unique = new Set(results.filter(r => r.configured).map(r => r.coinbase));
  console.log(`Found ${unique.size} unique coinbase address(es) across ${endpoints.length} nodes`);

  return results;
}

Error Handling

Common errors and solutions:

Error CodeDescriptionSolution
-32000Etherbase must be explicitly specifiedNode has no coinbase configured — set via client CLI flag
-32601Method not foundNode client may not support this method
-32603Internal errorNode may be initializing — retry after delay
-32005Rate limit exceededReduce request frequency