🛠️ `debug_traceCall` RPC Method (Base Chain)

The debug_traceCall method simulates a transaction without sending it, then returns a detailed trace of what would happen if it were executed on-chain — all within the context of a specific block.

This is especially useful for debugging contract calls, testing edge cases, and exploring how gas, storage, and logic behave — before actually executing the transaction.

Parameters

1. Transaction Call Object [required]

This is the same structure as an eth_call. You describe the transaction you want to simulate:

from (optional) — The sender address
to (required) — Target contract or recipient
gas (optional) — Gas limit (not charged, but may affect simulation)
gasPrice (optional) — Gas price in hex
value (optional) — ETH or token value to send
data (optional) — Encoded function call (ABI). Learn ABI basics (opens in a new tab)

2. Block Parameter [required]

Pick which block context the simulation should run in:

Hex block number (e.g. "0xA12BC")
"latest", "earliest", "pending"
"safe" / "finalized" (only supported on Ethereum + Arbitrum)

📖 More about block tags (opens in a new tab)

💡

Confused about input formatting? Ask in the Chainnodes Telegram Chat (opens in a new tab)

3. Trace Type & Options [optional]

You can specify a custom tracer for deeper debugging.

tracer (string) — Choose one:
- callTracer: Tracks internal calls, inputs, outputs, reverts
- prestateTracer: Shows balance, nonce, and storage touched
tracerConfig (object) — Optional advanced options:
- onlyTopCall — Skip sub-calls and only trace the main one

Extra config for advanced tracing (optional):

Option	Description
`disableStorage`	Skip storage tracing (faster)
`disableStack`	Skip EVM stack changes
`disableMemory`	Skip memory tracking
`disableReturnData`	Don’t trace return value
`timeout`	Set a timeout (default: `5s`) for complex traces

💡

If you specify a tracer like callTracer, options like disableMemory, disableStack, etc. will be ignored.

If you don’t set a tracer, the method will fall back to Geth's built-in opcode logger (opens in a new tab).

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Returns

If using `callTracer`

Field	Description
`type`	Type of call (CALL, DELEGATECALL, etc.)
`from`	Sender
`to`	Recipient
`gas`	Gas supplied
`gasUsed`	Gas used
`value`	Transferred amount
`input`	Calldata
`output`	Return value
`error`	Error message (if any)
`calls`	Internal sub-calls
`revertReason`	If reverted, the revert message

If using `prestateTracer`

Shows contract state touched by the simulation:
- balance — Current ETH balance
- code — Bytecode
- nonce — Transaction count
- storage — Mapped storage slots

If using no tracer (`Struct/opcode` default)

Returns an EVM step-by-step trace:

gas — Total gas used
failed — Whether execution failed
returnValue — What the contract returned
structLogs — Execution log for each opcode step:
- pc, op, gas, gasCost
- stack, memory, storage
- depth — Call depth
- refund, error

Request

POST https://base-mainnet.chainnodes.org/YOUR-API-KEY

Example

HTTPS POST Request with a JSON RPC call in the body
Replace YOUR-API-KEY with the API key from your CHAINNODES Dashboard (opens in a new tab)
You can use a different supported network by replacing base-mainnet

curl https://base-mainnet.chainnodes.org/YOUR-API-KEY \
    -X POST \
    -H "Content-Type: application/json" \
    -d '{"method":"debug_traceCall","params":[{"to": "0x6d2e03b7effeae98bd302a9f836d0d6ab0002766", "gasPrice": "0x174876E800"} ,"latest" ],"id":1,"jsonrpc":"2.0"}'

Body

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "structLogs": [],
    "gas": 21000,
    "failed": false,
    "returnValue": ""
  }
}

JSON-RPC Base API Documentation by CHAINNODES is based on Erigon node client. Contact us if you are interested in specific methods that are only available on geth, besu, Nethermind or reth

debug_traceBlockByNumber debug_traceTransaction

🛠️ debug_traceCall RPC Method (Base Chain)