debug_traceBlockByNumber

debug_traceBlockByNumber re-executes every transaction in an Avalanche C-Chain block and returns an opcode-level trace for each, with the block chosen by its height or by a tag such as latest. The C-Chain is Avalanche's EVM chain, where gas is paid in AVAX and the Snowman engine finalizes blocks in roughly one to two seconds, which makes latest a moving target you should use deliberately. Send the request to https://avalanche.therpc.io/YOUR_API_KEY (chain ID 43114, hex 0xa86a). The result is an array of per-transaction traces in block order, each shaped by the tracer you select.

Use cases

• Trace all transactions in a known C-Chain block height to audit every state transition the Snowman engine finalized at once.
• Extract the complete call graph for an entire block for MEV research across Avalanche DeFi (Trader Joe, GMX, Aave) using callTracer.
• Compare the gas profiles of every transaction in a block to spot AVAX-cost outliers and inefficient contracts.

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_traceBlockByNumber",
7    "params": [
8        "latest",
9        {}
10      ],
11    "id": 1
12  }'

Try it live in the Avalanche playground.

Errors & troubleshooting

Common pitfalls

• Tracing a full block replays every transaction in it; a busy Avalanche block can take minutes and return gigabytes of structLog data.
• Historical blocks need an archive node; a pruned C-Chain node only holds recent state and returns block not found for older heights.
• Because the C-Chain produces a new block every second or two, the latest tag can race with block production — pin a concrete height for reproducible results.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• debug_traceBlockByHash
• 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_traceBlockByNumber","params":["latest",{}]}'