debug_traceTransaction

debug_traceTransaction replays a historical OP Mainnet transaction at the opcode level, reproducing the exact EVM state of the block where it was included. Given a transaction hash, the node re-executes it step by step and emits a trace — by default a struct-log stream, or a structured result if you select a tracer like callTracer or prestateTracer. OP Mainnet is the OP Stack rollup that meters gas in ETH and settles to Ethereum L1; send the request to https://optimism.therpc.io/YOUR_API_KEY (chain ID 10, 0xa) to see precisely what happened inside any past transaction.

Use cases

• Find out why an OP Mainnet contract call reverted by inspecting the exact opcode and stack state at the REVERT instruction.
• Profile per-opcode gas consumption to locate hot spots when optimizing L2 execution costs.
• Reconstruct the full internal call tree of an MEV bundle on OP Mainnet using callTracer.
• Capture pre-execution account and storage state with prestateTracer for security post-mortems after an exploit.

Parameters

Response

Example request

1curl https://optimism.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 Optimism playground.

Errors & troubleshooting

Common pitfalls

• Any OP Mainnet transaction older than the most recent few thousand blocks needs an archive node; pruned nodes cannot reproduce its state.
• Default struct-log output can reach hundreds of MB for complex transactions; switch to callTracer or disable stack/storage via the options to shrink it.
• Custom JavaScript tracers run in a sandboxed interpreter and may hit the node's timeout on long-running transactions.

Supported networks

• Mainnet — Chain ID: 10
• Sepolia — Chain ID: 11155420

See also

• debug_traceCall
• debug_traceBlockByHash
• trace_transaction
• trace_replayTransaction

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