trace_call

trace_call simulates a call against a chosen block's state on the Avalanche C-Chain and returns an OpenEthereum-style call-tree trace, plus an optional opcode-level VM trace and an optional state diff — without ever creating a transaction or spending AVAX. The C-Chain is Avalanche's EVM chain, where gas is paid in AVAX and Snowman consensus settles blocks in roughly one to two seconds. You pick exactly which artifacts you want via the traceTypes array ("trace", "vmTrace", "stateDiff"). Send the request to https://avalanche.therpc.io/YOUR_API_KEY (chain ID 43114, hex 0xa86a), and the response bundles the call output together with whichever trace types you requested.

Use cases

• Preview all internal calls a transaction would generate on the C-Chain before broadcasting it and paying AVAX gas.
• Request stateDiff to validate the exact storage and balance changes a prospective transaction would make on a DeFi contract like Aave or Trader Joe.
• Test smart-contract logic against a historical Avalanche block state (past blocks require an archive node).

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": "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 Avalanche playground.

Errors & troubleshooting

Common pitfalls

• Requesting all three trace types (trace + vmTrace + stateDiff) at once can produce a very large response; ask only for what you actually need.
• Historical C-Chain states require an archive node with the trace API enabled, which many public Avalanche endpoints do not provide.
• The vmTrace format is Parity-specific and differs from Geth's debug_traceCall structLog — do not feed one into tooling built for the other.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• trace_transaction
• debug_traceCall
• trace_replayTransaction
• trace_filter

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