Arbitrum One

Arbitrum One

eth_getUncleByBlockHashAndIndex

The eth_getUncleByBlockHashAndIndex method returns information about an uncle (ommer) block by a block hash and uncle index position.

Use Cases

• Analyzing blockchain network health
• Verifying uncle rewards distribution
• Researching mining/validation competition
• Studying blockchain throughput and latency
• Understanding network security through uncle rate
• Mining strategy analysis
• Historical blockchain research
• Block confirmation verification

Method Details

Returns information about the uncle (ommer) block by the block hash and uncle index position.

Response Example

1{
2	"jsonrpc": "2.0",
3	"id": 1,
4	"result": {
5		"difficulty": "0x57f17a09378",
6		"extraData": "0x476574682f76312e302e302f6c696e75782f676f312e342e32",
7		"gasLimit": "0x1388",
8		"gasUsed": "0x0",
9		"hash": "0x932bdf904546a2287a2c9b2ede37925f698a7657484b172d4e5184f80bdd464d",
10		"logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
11		"miner": "0xbb7b8287f3f0a933474a79eae42cbca977791171",
12		"mixHash": "0x4500aa4ee2b3044a155252e35273770edeb2ab6f8cb19ca8e732771484462169",
13		"nonce": "0x24732773618271bc",
14		"number": "0x299",
15		"parentHash": "0xa779859b1ee558258b7008bbabff272280136c5dd3eb3ea3bfa8f6ae03bf91e5",
16		"receiptsRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
17		"sha3Uncles": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
18		"size": "0x21d",
19		"stateRoot": "0x2604fbf5183f5360da249b51f1b9f1e0f315d2ff3ffa1a4143ff221ad9ca1fec",
20		"timestamp": "0x55ba4827",
21		"totalDifficulty": null,
22		"transactionsRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
23		"uncles": []
24	}
25}

Understanding Uncle Blocks

Uncle blocks (also called ommers) are valid blocks that were mined but not included in the main blockchain. This happens when two miners find a valid block at nearly the same time, but only one can be accepted into the main chain.

Why Uncle Blocks Matter

• Network Security: A high uncle rate may indicate network latency or high mining competition
• Rewards: Miners of uncle blocks receive partial rewards (2/32 of block reward pre-EIP-1559)
• Block Inclusion: Uncles are referenced in regular blocks (up to 2 per block)
• Chain Confirmation: Uncles contribute to blockchain security despite not being in the main chain

Uncle Rewards Calculation

Uncle block miners receive rewards based on the formula:

((Uncle Block Number + 8) - Main Block Number) * (Block Reward / 8)

Where:

• Uncle Block Number is the block number of the uncle block
• Main Block Number is the block number that included the uncle reference
• Block Reward is the standard block reward (varies by network upgrade)

Important Notes

• Uncle blocks contain header information only, no transactions
• Uncles must be within 6 blocks of the including block
• Post-Merge (PoS), uncles no longer exist as validators produce blocks in slots
• The uncle rate is an important network health metric
• Uncle information can be vital for analyzing historical blockchain data

See also

• eth_getUncleByBlockNumberAndIndex - Get uncle block data using the block number and uncle index
• eth_getUncleCountByBlockHash - Count the number of uncles in a block using its hash
• eth_getBlockByHash - Get full block information including uncle references

1curl https://arbitrum.therpc.io \
2  -X POST \
3  -H 'Content-Type: application/json' \
4  -d '{"jsonrpc":"2.0","id":1,"method":"eth_getUncleByBlockHashAndIndex","params":["0xc8df1f061abb4d0c107b2b1a794ade8780b3120e681f723fe55a7be586d95ba6","0x0"]}'