eth_getUncleByBlockNumberAndIndex

eth_getUncleByBlockNumberAndIndex is the height-based counterpart to the hash variant: on proof-of-work chains it returns the uncle (ommer) block header at a given index within the block at a specified height or block tag. On the Avalanche C-Chain (chain ID 43114, fees paid in AVAX), blocks are finalized by the Snowman/Avalanche BFT protocol rather than mined competitively, so no uncle blocks ever exist and this method returns null at every height — including latest. It remains exposed at https://avalanche.therpc.io/YOUR_API_KEY so standard EVM clients that probe for uncles keep working against the C-Chain.

Use cases

• Scanning a range of C-Chain blocks by number to collect uncle headers for uncle-rate analysis: this will return null for every block, since Avalanche produces no uncles.
• Reaching genesis-era data with a block tag such as earliest: convenient for height-based access in general, but on the C-Chain there are no uncle headers to retrieve at any height; use eth_getBlockByNumber for the canonical header instead.

Parameters

Response

Example request

1curl https://avalanche.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "eth_getUncleByBlockNumberAndIndex",
7    "params": [
8        "latest",
9        "0x0"
10      ],
11    "id": 1
12  }'

Try it live in the Avalanche playground.

Errors & troubleshooting

Common pitfalls

• The Avalanche C-Chain has no proof-of-work mining and uses Snowman/Avalanche BFT finality, so it produces no uncles; this method returns null for recent blocks and for latest alike — do not treat an empty result as an error.
• Even where uncles do exist on other networks, an uncle header carries no transactions array — but on the C-Chain you will never receive a header from this call in the first place.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• eth_getUncleByBlockHashAndIndex
• eth_getUncleCountByBlockNumber
• eth_getBlockByNumber

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