eth_getUncleByBlockHashAndIndex

eth_getUncleByBlockHashAndIndex is the Ethereum JSON-RPC call that, on proof-of-work chains, returns the uncle (ommer) block header at a given index within the block identified by a hash. On the Avalanche C-Chain (chain ID 43114, gas paid in AVAX) it is part of the standard EVM API surface but has no real data to return: blocks are produced under the Snowman/Avalanche BFT consensus, not by competing miners, so the chain never creates uncle blocks. As a result this method returns null for every block. The endpoint is https://avalanche.therpc.io/YOUR_API_KEY; the call exists purely so EVM tooling that expects it continues to work against the C-Chain.

Use cases

• Computing uncle reward amounts for mining analysis: not applicable on the C-Chain, since Snowman consensus pays no uncle rewards and this call returns null.
• Measuring uncle rates as a proxy for network latency or mining competition: not meaningful here — the C-Chain has no mining race, so there are no uncle rates to measure.
• Retrieving uncle header data for blockchain research: on Avalanche this always yields null; for header research, fetch the canonical block header instead with eth_getBlockByHash.

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_getUncleByBlockHashAndIndex",
7    "params": [
8        "0x0000000000000000000000000000000000000000000000000000000000000000",
9        "0x0"
10      ],
11    "id": 1
12  }'

Try it live in the Avalanche playground.

Errors & troubleshooting

Common pitfalls

• Even on chains that do produce uncles, an uncle header carries no transactions array — but on the Avalanche C-Chain this is moot, because the call never returns a header at all.
• The C-Chain uses Snowman/Avalanche BFT finality rather than proof-of-work, so it produces no uncle blocks; this method returns null for any block hash and uncle index, including the most recent blocks.
• Do not build logic that depends on an uncle ever being found here — index 0x0, 0x2, or any other index all return null on Avalanche. Use eth_getBlockByHash for real block header data.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• eth_getUncleByBlockNumberAndIndex
• eth_getUncleCountByBlockHash
• eth_getBlockByHash

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_getUncleByBlockHashAndIndex","params":["0x0000000000000000000000000000000000000000000000000000000000000000","0x0"]}'