debug_traceBlockByHash

debug_traceBlockByHash re-executes every transaction in a single Avalanche C-Chain block and returns an opcode-level execution trace for each, with the block selected by its hash. The C-Chain is Avalanche's EVM chain, where AVAX is the gas token and the Snowman consensus engine finalizes blocks in about one to two seconds — so identifying a block by hash is the most precise way to trace it, since the hash is unambiguous even around a reorg. Send the call to https://avalanche.therpc.io/YOUR_API_KEY (chain ID 43114, hex 0xa86a). You get back one trace result per transaction, in block order, shaped by whichever tracer you configure.

Use cases

• Deterministically trace one specific C-Chain block when you hold only its hash, for example while investigating a short Avalanche reorg.
• Audit every internal call inside a known side-chain or non-canonical block that the Snowman engine did not finalize.
• Build a block-level call graph for MEV analysis on Avalanche DeFi venues like Trader Joe or GMX using callTracer.

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

Try it live in the Avalanche playground.

Errors & troubleshooting

Common pitfalls

• This costs the same as debug_traceBlockByNumber — it replays every transaction in the block, so the work scales with how busy the C-Chain block was, not with the lookup key.
• Historical Avalanche blocks need an archive node; a pruned node only holds recent state and returns block not found for older hashes.
• A block packed with complex DeFi transactions can exceed the default tracer timeout on a remote node; use a compact tracer or raise the timeout for dense blocks.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• debug_traceBlockByNumber
• debug_traceBlock
• debug_traceTransaction
• trace_block

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":"debug_traceBlockByHash","params":["0x0000000000000000000000000000000000000000000000000000000000000000",{}]}'