debug_traceCall

debug_traceCall runs a call against a chosen block's state on the Avalanche C-Chain and returns a full opcode-level trace, all without ever submitting a transaction or spending any AVAX. The C-Chain is Avalanche's EVM chain, where gas is denominated in AVAX and Snowman consensus finalizes blocks in roughly one to two seconds. Because nothing is broadcast, you can probe how a call would behave — its execution path, revert reason, and gas profile — entirely off-chain. Send the request to https://avalanche.therpc.io/YOUR_API_KEY (chain ID 43114, hex 0xa86a), optionally with state and block overrides, and the response mirrors debug_traceTransaction for the tracer you pick.

Use cases

• Debug a C-Chain contract interaction before broadcasting by tracing the exact execution path and capturing the revert reason.
• Simulate how a call would have behaved at a historical Avalanche block height (past blocks require an archive node).
• Profile the gas cost of a prospective transaction on a DeFi protocol like Aave or Trader Joe without spending any AVAX.
• Test proposed contract-logic changes against live C-Chain state using stateOverrides to inject modified bytecode.

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

Try it live in the Avalanche playground.

Errors & troubleshooting

Common pitfalls

• The call runs against the named block's state, so results can diverge from real execution when the logic depends on block context such as block.timestamp or the C-Chain coinbase — use blockOverrides to control these.
• Historical block states require an archive node; a pruned Avalanche node only retains recent state.
• The response can be very large for complex contracts; use a compact tracer like callTracer, or disable stack, memory, and storage capture in the options.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• debug_traceTransaction
• trace_call
• debug_storageRangeAt
• debug_traceBlockByNumber

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