debug_traceCall on Unichain

Measured 2026-10-04 by our weekly probe, which calls debug_traceCall through the same Unichain endpoint customers use.

What debug_traceCall does

Executes a call against a block's state and returns its execution trace (with a tracer such as callTracer), without sending a transaction. It is the standard way to see what a call would do internally before you submit it.

debug_traceCall on Unichain: what we measured

• Default Unichain routing keeps state for roughly the last 1,000,000 blocks (about 11.6 days of Unichain history). Tracing against a block older than that needs historical state. Add &archive=1 to send the request to archive upstreams (paid plans).

Example request

curl -s https://rpc.swiftnodes.io/rpc/unichain?key=YOUR_API_KEY \
  -X POST -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"debug_traceCall","params":[{"to":"0x0000000000000000000000000000000000000000","data":"0x"},"latest",{"tracer":"callTracer"}]}'

import { createPublicClient, http } from "viem";

const client = createPublicClient({ transport: http("https://rpc.swiftnodes.io/rpc/unichain?key=YOUR_API_KEY") });

// Any JSON-RPC method, typed loosely: debug_traceCall on Unichain
const result = await client.request({
  method: "debug_traceCall",
  params: [{"to":"0x0000000000000000000000000000000000000000","data":"0x"},"latest",{"tracer":"callTracer"}],
});

Other methods on Unichain

• eth_getLogsSupported
• eth_getBlockReceiptsSupported
• eth_feeHistorySupported
• eth_getProofSupported
• eth_createAccessListSupported
• trace_blockSupported
• trace_transactionSupported

debug_traceCall on other chains

Support differs by chain; the full measured table is on the debug_traceCall reference.

• Ethereum
• Base
• Arbitrum
• Optimism
• Polygon
• BNB Smart Chain
• Avalanche
• Sonic
• Linea
• Scroll
• zkSync Era
• Blast
• Mantle
• Gnosis
• Celo
• Berachain
• Monad
• Kaia
• PulseChain

Frequently asked questions