trace_call

trace_call runs a call against a chosen block's state and traces it, without ever broadcasting a transaction. The result can include an OpenEthereum-style call-tree trace, an optional opcode-level VM trace, and an optional state diff. BSC settles in BNB and runs the BEP-20 contracts behind venues like PancakeSwap, so this is how you preview what a router or swap call would actually do before committing gas to it. Send the request to chain ID 56 at https://bsc.therpc.io/YOUR_API_KEY. The traceTypes array decides which artifacts get computed, keeping the response to the detail you asked for. Simulating against a past block pulls in historical state, which makes it a heavy call that needs a trace-enabled archive node.

Use cases

• Map the full call tree a transaction would spawn before you broadcast it.
• Ask for stateDiff to confirm a prospective transaction touches exactly the balances and storage slots you expect, and nothing more.
• Test contract logic against a historical BSC block state, which calls for a trace-enabled archive node.

Parameters

Response

Example request

1curl https://bsc.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 BNB Smart Chain playground.

Errors & troubleshooting

Common pitfalls

• Asking for trace, vmTrace, and stateDiff together can balloon the response, so request only the artifacts you actually need.
• Historical block states require a node running the trace API over archive data, which lower tiers may not provide.
• The vmTrace output uses a Parity-specific shape that differs from the structLog Geth returns from debug_traceCall.

Supported networks

• Mainnet — Chain ID: 56
• Testnet — Chain ID: 97

See also

• trace_transaction
• debug_traceCall
• trace_replayTransaction
• trace_filter

1curl https://bsc.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":"0x8894E0a0c962CB723c1976a4421c95949bE2D4E3","data":"0x"},[],"latest"]}'