eth_getBlockByHash

eth_getBlockByHash returns the full block data for the L2 block identified by a given 32-byte hash on Arbitrum One, the Optimistic Rollup whose gas is paid in ETH. Pass the block hash and a boolean for whether you want full transaction objects or just their hashes, and the Nitro node replies with the header, gas metrics, and transaction list. Send the request to https://arbitrum.therpc.io/YOUR_API_KEY (chain ID 42161).

Use cases

• Fetch full block data when you already hold a specific Arbitrum One block hash, e.g. one pulled from a transaction receipt.
• Detect reorgs near the sequencer tip by comparing a stored hash against what the node now returns for that block number — relevant since Arbitrum soft confirmations precede L1-backed finality.
• Retrieve gas metrics, timestamp, and header fields for a specific canonical L2 block for indexing or analytics.

Parameters

Response

Example request

1curl https://arbitrum.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "eth_getBlockByHash",
7    "params": [
8        "0x0000000000000000000000000000000000000000000000000000000000000000",
9        false
10      ],
11    "id": 1
12  }'

Try it live in the Arbitrum One playground.

Errors & troubleshooting

Common pitfalls

• Pass a real boolean for includeTransactions, not the string "true" — JSON-RPC requires the boolean type or the node rejects the call.
• With includeTransactions=true, a busy Arbitrum One block — high-throughput GMX or Uniswap activity packs many transactions — can exceed 1 MB; stream or paginate when bandwidth is tight.
• The method returns null for an unknown hash; always null-check before reading fields rather than assuming a block object came back.

Supported networks

• Mainnet — Chain ID: 42161
• Sepolia — Chain ID: 421614

See also

• eth_getBlockByNumber
• eth_getBlockReceipts
• eth_getTransactionByHash
• eth_getBlockTransactionCountByHash

1curl https://arbitrum.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H 'Content-Type: application/json' \
4  -d '{"jsonrpc":"2.0","id":1,"method":"eth_getBlockByHash","params":["",""]}'