eth_getUncleCountByBlockNumber

eth_getUncleCountByBlockNumber returns the number of uncle blocks referenced by the block at a given height or block tag (such as latest). On the Avalanche C-Chain (chain ID 43114, gas paid in AVAX), this is always 0x0: under Snowman/Avalanche BFT consensus there is no competitive mining and therefore no uncle (ommer) blocks at any height. Available at https://avalanche.therpc.io/YOUR_API_KEY, the method is kept for EVM tooling compatibility, but on this chain you can treat its result as a constant 0x0.

Use cases

• Scanning a sequential range of blocks for uncle presence to compute an uncle rate: on the C-Chain every height returns 0x0, so the rate is uniformly zero and the scan is unnecessary.
• A quick check before fetching uncle details by number: the count is always 0x0 here, so there is never a follow-up eth_getUncleByBlockNumberAndIndex call to make.

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_getUncleCountByBlockNumber",
7    "params": ["latest"],
8    "id": 1
9  }'

Try it live in the Avalanche playground.

Errors & troubleshooting

Common pitfalls

• On the Avalanche C-Chain this method returns 0x0 regardless of the height or block tag you pass, because Snowman consensus produces no uncles — there is no block where the count is non-zero.
• The result is a hex string ("0x0"), not a number — parse it (for example with parseInt(value, 16)) before any numeric comparison.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• eth_getUncleByBlockNumberAndIndex
• eth_getUncleCountByBlockHash
• 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_getUncleCountByBlockNumber","params":[""]}'