debug_traceTransaction

debug_traceTransaction replays a transaction that already landed on Arbitrum One, opcode by opcode, reproducing the exact EVM state at the block where it was mined. You pass the transaction hash and an optional tracer config, and the node re-executes the transaction against its historical ArbOS state. Arbitrum One is a Nitro Optimistic Rollup (chain ID 42161) that pays gas in ETH, so this trace shows the real L2 execution behind any tx you find on Arbiscan. Send the request to https://arbitrum.therpc.io/YOUR_API_KEY.

Use cases

• Determine why an Arbitrum One contract call reverted by inspecting the exact opcode and stack state at the REVERT instruction.
• Profile per-opcode gas use to find hot spots worth optimizing — useful since Arbitrum L2 execution gas is only one half of the total fee.
• Reconstruct the full internal call tree of an MEV bundle with callTracer across Arbitrum DeFi venues like GMX and Camelot.
• Capture pre-execution account and storage state with prestateTracer for a security post-mortem of an exploited contract.

Parameters

Response

Example request

1curl https://arbitrum.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 Arbitrum One playground.

Errors & troubleshooting

Common pitfalls

• Any transaction older than the most recent few thousand Arbitrum One blocks needs an archive node holding that ArbOS state, or you get "transaction not found" (-32000).
• The default struct-log output can reach hundreds of MB for a complex transaction; switch to a compact tracer like callTracer or disable stack/storage in the options.
• Custom JavaScript tracers run in a sandboxed interpreter and may hit the timeout on long-running transactions — a real risk on dense Arbitrum DeFi calls.

Supported networks

• Mainnet — Chain ID: 42161
• Sepolia — Chain ID: 421614

See also

• debug_traceCall
• debug_traceBlockByHash
• trace_transaction
• trace_replayTransaction

1curl https://arbitrum.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":["",{}]}'