web3_sha3

web3_sha3 computes the Keccak-256 hash of hex-encoded input and returns it as a 32-byte hex value. Despite the "sha3" in the name, this is Keccak-256 — the original submission, not the later NIST SHA3-256 standard — which is exactly the hash function the Avalanche C-Chain EVM uses for event topics, function selectors, and storage slots. Since the C-Chain is EVM-equivalent (the chain where AVAX pays for gas under Snowman/Avalanche consensus), the hashes it produces match what your contracts compute on-chain. Send the request to https://avalanche.therpc.io/YOUR_API_KEY (chain ID 43114, 0xa86a).

Use cases

• Compute event topic hashes — the Keccak-256 of an event signature like Transfer(address,address,uint256) — to build the topics array for eth_getLogs filters against C-Chain contracts such as Aave or Trader Joe.
• Generate 4-byte function selectors by hashing a function signature and taking the first four bytes, useful for decoding or constructing calldata for eth_call.

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": "web3_sha3",
7    "params": ["0x"],
8    "id": 1
9  }'

Try it live in the Avalanche playground.

Errors & troubleshooting

Common pitfalls

• The input must be 0x-prefixed hex-encoded bytes, not a raw UTF-8 string. To hash text like an event signature, encode it to hex first; passing the plain string yields the wrong hash or an "invalid argument" error.
• Keccak-256 is not the same as NIST SHA3-256. A standard library sha3 function will produce different output unless it specifically implements the Ethereum Keccak variant — make sure your local tooling uses the right one so it agrees with what the C-Chain computes.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• eth_call
• eth_getLogs

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":"web3_sha3","params":["0x"]}'