debug_traceTransaction

debug_traceTransaction replays a confirmed Avalanche C-Chain transaction opcode by opcode, reproducing the exact EVM state at the block in which it was included. The C-Chain is Avalanche's EVM chain, where AVAX pays for gas and Snowman consensus finalizes blocks in about one to two seconds, so a traced transaction is replayed against the precise state the network agreed on. Send the call to https://avalanche.therpc.io/YOUR_API_KEY (chain ID 43114, hex 0xa86a) with the transaction hash. The default tracer returns a full structLog of every executed instruction; alternative tracers such as callTracer and prestateTracer give you a call tree or a pre-execution state map instead.

Use cases

• Find out why a C-Chain contract call reverted by inspecting the exact opcode and stack state at the REVERT instruction.
• Profile per-opcode gas use to spot hot spots and trim the AVAX cost of a frequently called contract.
• Reconstruct the full internal call tree of an MEV bundle on Avalanche venues like Trader Joe or GMX using callTracer.
• Capture pre-execution account state with prestateTracer for a security post-mortem of an exploited C-Chain contract.

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

Try it live in the Avalanche playground.

Errors & troubleshooting

Common pitfalls

• Any transaction older than the most recent few thousand C-Chain blocks needs an archive node; a pruned Avalanche node returns transaction not found for older state.
• The default structLog can reach hundreds of MB for a complex transaction; use a compact tracer like callTracer or disable stack and storage capture via the options object.
• Custom JavaScript tracers run in a sandboxed interpreter and may hit the configured timeout on long-running, gas-heavy transactions.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• debug_traceCall
• debug_traceBlockByHash
• trace_transaction
• trace_replayTransaction

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_traceTransaction","params":["",{}]}'