eth_getUncleCountByBlockHash

eth_getUncleCountByBlockHash returns the number of uncle blocks referenced by the block identified by a given hash. On the Avalanche C-Chain (chain ID 43114, gas paid in AVAX), that count is always 0x0: the chain reaches consensus through the Snowman/Avalanche BFT protocol rather than proof-of-work mining, so blocks never reference uncles (ommers). The method stays available at https://avalanche.therpc.io/YOUR_API_KEY for compatibility with EVM clients and indexers that expect the full Ethereum JSON-RPC method set, but on this chain it is effectively a constant 0x0.

Use cases

• Checking whether a block has uncles before calling eth_getUncleByBlockHashAndIndex: on the C-Chain the count is always 0x0, so you can skip the follow-up call entirely.
• Building an uncle-rate time series for network-health research: not meaningful on Avalanche, where Snowman consensus yields a flat 0x0 uncle count across all blocks; track finality time or block production 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_getUncleCountByBlockHash",
7    "params": ["0x0000000000000000000000000000000000000000000000000000000000000000"],
8    "id": 1
9  }'

Try it live in the Avalanche playground.

Errors & troubleshooting

Common pitfalls

• Because the C-Chain has never used proof-of-work, every block returns 0x0 here; there is no historical era on this chain where the count is non-zero.
• A hash that does not match any known block returns null rather than 0x0 — distinguish "unknown block" (null) from "known block, no uncles" (0x0) when handling the response.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• eth_getUncleByBlockHashAndIndex
• eth_getUncleCountByBlockNumber
• 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_getUncleCountByBlockHash","params":["0x0000000000000000000000000000000000000000000000000000000000000000"]}'