trace_call

trace_call simulates a call against a chosen OP Mainnet block state and returns an OpenEthereum-style call-tree trace, plus an optional opcode-level VM trace and an optional state diff — all without creating a transaction or spending any ETH. You pick which outputs you want via the traceTypes array (trace, vmTrace, stateDiff), so it doubles as a preview tool and a storage-impact analyzer. OP Mainnet is the OP Stack rollup with ETH gas, chain ID 10 (0xa); send the request to https://optimism.therpc.io/YOUR_API_KEY to see a call's full effect before committing.

Use cases

• Preview every internal call a prospective OP Mainnet transaction would generate before broadcasting it.
• Request stateDiff to validate the exact balance and storage changes a transaction would make against what you expect.
• Test smart-contract logic against a historical OP Mainnet block state (requires a trace-enabled archive node).

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": "trace_call",
7    "params": [
8        {
9          "to": "0x0000000000000000000000000000000000000000",
10          "data": "0x"
11        },
12        [
13          "trace"
14        ],
15        "latest"
16      ],
17    "id": 1
18  }'

Try it live in the Optimism playground.

Errors & troubleshooting

Common pitfalls

• Requesting all three trace types at once (trace + vmTrace + stateDiff) can produce very large responses; ask only for the outputs you actually need.
• Simulating against a historical OP Mainnet block requires an archive node with the trace API enabled.
• The vmTrace format is Parity-specific and differs from the Geth debug_traceCall struct-log format — do not parse one as the other.

Supported networks

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

See also

• trace_transaction
• debug_traceCall
• trace_replayTransaction
• trace_filter

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":"trace_call","params":[{"to":"0x0000000000000000000000000000000000000000","data":"0x"},[],"latest"]}'