chain_getBlockHash - Manta Atlantic RPC Method

Returns the block hash for a given block number on Manta Atlantic. This is the primary method for converting block numbers into block hashes, which are required by most other chain RPC methods.

Why Manta Atlantic? Build on the ZK Layer 1 on Polkadot enabling private transactions and on-chain compliance identities with zkSNARK-powered privacy, modular compliance identities, MANTA token staking hub, and end-to-end transaction privacy.

When to Use This Method

chain_getBlockHash is fundamental for privacy-focused developers, DeFi builders requiring private swaps, and teams needing zkSNARK capabilities:

• Historical Queries — Convert block numbers to hashes for state queries at specific heights on Manta Atlantic
• Block Navigation — Navigate the blockchain history for private asset transfers, zkNFTs, on-chain compliance identities, and private parachain asset swaps
• Data Indexing — Build block number-to-hash mappings for indexers and explorers
• Cross-Reference — Translate block numbers from events or logs into hashes for detailed lookups

Code Examples

Common Use Cases

1. Block Range Iterator

Iterate over a range of blocks on Manta Atlantic for indexing:

async function iterateBlocks(api, startBlock, endBlock) {
  for (let num = startBlock; num <= endBlock; num++) {
    const hash = await api.rpc.chain.getBlockHash(num);
    const block = await api.rpc.chain.getBlock(hash);

    console.log(`Block #${num}: ${block.block.extrinsics.length} extrinsics`);
  }
}

2. Historical State Query

Query Manta Atlantic state at a specific block height:

async function getBalanceAtBlock(api, address, blockNumber) {
  const blockHash = await api.rpc.chain.getBlockHash(blockNumber);
  const apiAt = await api.at(blockHash);
  const account = await apiAt.query.system.account(address);

  return {
    blockNumber,
    free: account.data.free.toString(),
    reserved: account.data.reserved.toString()
  };
}

3. Genesis Hash Verification

Verify you are connected to the correct Manta Atlantic network:

async function verifyNetwork(api, expectedGenesisHash) {
  const genesisHash = await api.rpc.chain.getBlockHash(0);

  if (genesisHash.toHex() !== expectedGenesisHash) {
    throw new Error(`Wrong network! Expected ${expectedGenesisHash}, got ${genesisHash.toHex()}`);
  }

  console.log('Connected to correct network');
}

Error Handling

Related Methods

• chain_getBlock — Get full block data by hash
• chain_getHeader — Get block header by hash
• chain_getFinalizedHead — Get the latest finalized block hash