eth_getUncleByBlockHashAndIndex

The eth_getUncleByBlockHashAndIndex method returns information about an uncle block (also called ommer block) by block hash and uncle index position. Uncle blocks are valid blocks that were mined but not included in the main canonical chain, typically due to network propagation delays causing temporary forks.

This method is useful for analyzing blockchain consensus mechanics, studying mining statistics and fork rates, understanding network health and propagation efficiency, and researching uncle/ommer rewards. Note that Kaia transitioned to Proof of Stake with The Merge (September 2022), after which uncle blocks no longer exist. This method is primarily relevant for historical analysis of pre-Merge blocks or for networks still using Proof of Work. Uncle blocks included in the canonical chain earn reduced rewards for their miners.

Parameters

parameter	type	description
blockHash	string (required)	Hash of the block (32 bytes)
uncleIndex	string (required)	Uncle block index position in hex

Return Object

The method returns an uncle block object, or null if no uncle exists at the specified index:

field	type	description
number	string	The block number of the uncle block (hex)
hash	string	Hash of the uncle block (32 bytes)
parentHash	string	Hash of the parent block (32 bytes)
nonce	string	Proof-of-work nonce (8 bytes)
sha3Uncles	string	SHA3 hash of the uncles data in the block (32 bytes)
logsBloom	string	Bloom filter for the logs of the block (256 bytes)
transactionsRoot	string	Root of the transaction trie (32 bytes)
stateRoot	string	Root of the final state trie (32 bytes)
receiptsRoot	string	Root of the receipts trie (32 bytes)
miner	string	Address of the miner who mined this uncle block (20 bytes)
difficulty	string	Difficulty for this uncle block (hex)
totalDifficulty	string	Total difficulty of the chain until this block (hex)
extraData	string	Extra data field of this block (hex-encoded)
size	string	Size of this block in bytes (hex)
gasLimit	string	Maximum gas allowed in this block (hex)
gasUsed	string	Total gas used by all transactions in this block (hex)
timestamp	string	Unix timestamp for when the block was collated (hex)
transactions	array	Array of transaction hashes
uncles	array	Array of uncle block hashes (typically empty for uncle blocks themselves)

Uncle blocks are complete block headers but were not added to the canonical chain. Returns null if the uncle index is out of range.

Request Example

Request

Response Example

Response