beefy_getFinalizedHead - Bridge Hub RPC Method

Returns the block hash of the latest BEEFY-finalized block on Bridge Hub. BEEFY (Bridge Efficiency Enabling Finality Yielder) provides additional finality proofs that are optimized for light clients and cross-chain bridges, using compact aggregated signatures instead of full GRANDPA justifications.

Why Bridge Hub? Build on Polkadot's trustless bridging parachain with $75M+ TVL via Snowbridge to Ethereum with on-chain BEEFY/Beacon light clients (no multisigs), 100+ ERC-20 tokens supported, 24+ parachain integrations, and 1-2 minute transfer times.

When to Use This Method

beefy_getFinalizedHead is important for cross-chain developers, bridge operators, and teams requiring trustless Ethereum-Polkadot transfers:

• Cross-Chain Bridges — Verify finality proofs efficiently for bridge operations on trustless ETH and ERC-20 bridging, cross-chain messaging, and parachain-to-Ethereum asset transfers
• Light Clients — Verify finality without downloading full GRANDPA justifications
• Trustless Bridges — Generate compact finality proofs that can be verified on external chains
• Bridge Monitoring — Track BEEFY finality progress relative to GRANDPA finality

Code Examples

Common Use Cases

1. Bridge Finality Verification

Verify BEEFY finality before relaying messages on a cross-chain bridge:

async function verifyBridgeFinality(api, targetBlockHash) {
  const beefyHead = await api.rpc.beefy.getFinalizedHead();
  const beefyBlock = await api.rpc.chain.getBlock(beefyHead);
  const beefyNumber = beefyBlock.block.header.number.toNumber();

  const targetBlock = await api.rpc.chain.getBlock(targetBlockHash);
  const targetNumber = targetBlock.block.header.number.toNumber();

  if (beefyNumber >= targetNumber) {
    console.log(`Block #${targetNumber} has BEEFY finality — safe to relay`);
    return true;
  } else {
    console.log(`Waiting: BEEFY at #${beefyNumber}, target at #${targetNumber}`);
    return false;
  }
}

2. BEEFY vs GRANDPA Finality Monitor

Track the gap between the two finality gadgets:

async function monitorFinalityGadgets(api) {
  setInterval(async () => {
    try {
      const [beefyHead, grandpaHead] = await Promise.all([
        api.rpc.beefy.getFinalizedHead(),
        api.rpc.chain.getFinalizedHead()
      ]);

      const [beefyBlock, grandpaBlock] = await Promise.all([
        api.rpc.chain.getBlock(beefyHead),
        api.rpc.chain.getBlock(grandpaHead)
      ]);

      const beefyNum = beefyBlock.block.header.number.toNumber();
      const grandpaNum = grandpaBlock.block.header.number.toNumber();
      const lag = grandpaNum - beefyNum;

      console.log(`GRANDPA: #${grandpaNum} | BEEFY: #${beefyNum} | Lag: ${lag} blocks`);
    } catch (error) {
      console.error('Monitor error:', error.message);
    }
  }, 12000);
}

BEEFY vs GRANDPA Finality

Availability

BEEFY is enabled on Polkadot and Kusama relay chains and some parachains. If BEEFY is not active on the chain you are querying, this method will return an error. Check chain documentation or try calling the method to confirm availability.

Error Handling

Related Methods

• chain_getFinalizedHead — Get GRANDPA finalized head
• grandpa_roundState — Monitor GRANDPA consensus state
• chain_subscribeFinalizedHeads — Subscribe to GRANDPA finalized blocks