debug_traceCall

debug_traceCall executes a call against a chosen Base block state and returns a full opcode-level trace, all without ever submitting a transaction or spending gas. It is the read-only, traced counterpart to eth_call: you provide the same call object, and the node runs it and records every step. Base is the OP Stack rollup built by Coinbase, where gas is paid in ETH and the chain settles to Ethereum L1. Send the request to https://base.therpc.io/YOUR_API_KEY (chain ID 8453, hex 0x2105) with the call object, a block parameter, a tracer config, and optional state or block overrides. Because nothing is broadcast, you can probe contract behavior on Base's live or historical state safely before committing anything on-chain.

Use cases

• Debug a Base contract interaction before broadcasting by tracing the exact execution path and reading the precise revert reason — handy for swaps routed through Aerodrome or Uniswap on Base.
• Simulate how a call would have behaved at a historical Base block height to reproduce a past condition (this needs an archive node for older blocks).
• Profile the gas a prospective Base transaction would consume without paying any ETH, so you can size the gas limit accurately.
• Test proposed contract logic against Base's live state by supplying code and state overrides, seeing the result before you deploy.

Parameters

Response

Example request

1curl https://base.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 Base playground.

Errors & troubleshooting

Common pitfalls

• The call is simulated against the specified block's state, so results can diverge from real execution when the contract reads block-specific context such as timestamp or the L2 block number — Base's roughly two-second cadence means these values shift quickly.
• Tracing against a historical Base block state requires an archive node; recent state works on a normal full node.
• For a complex Base contract the default struct-log output can be huge; switch to a compact tracer like callTracer or disable stack, memory, and storage in the options object.

Supported networks

• Mainnet — Chain ID: 8453
• Sepolia — Chain ID: 84532

See also

• debug_traceTransaction
• trace_call
• debug_storageRangeAt
• debug_traceBlockByNumber

1curl https://base.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",{}]}'