debug_traceCall on Mode

Measured 2026-10-11 by our weekly probe, which calls debug_traceCall through the same Mode 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 Mode: what we measured

• Default Mode routing keeps state for roughly the last 1,000,000 blocks (about 23.1 days of Mode 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/mode?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/mode?key=YOUR_API_KEY") });

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

Other methods on Mode

• eth_blockNumberSupported
• eth_chainIdSupported
• eth_getBalanceSupported
• eth_getBlockByNumberSupported
• eth_getTransactionByHashSupported
• eth_getTransactionReceiptSupported
• eth_callSupported
• eth_estimateGasSupported
• eth_gasPriceSupported
• eth_maxPriorityFeePerGasSupported
• eth_sendRawTransactionSupported
• eth_getTransactionCountSupported
• eth_getCodeSupported
• eth_subscribeNot available
• eth_getLogsSupported
• eth_getBlockReceiptsSupported
• eth_feeHistorySupported
• eth_getProofSupported
• eth_createAccessListSupported
• trace_blockSupported
• trace_transactionNot available

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
• Unichain
• Kaia
• PulseChain
• World Chain
• Ronin
• Abstract
• ApeChain
• MegaETH
• Fantom
• Lisk
• Hemi
• X Layer
• BOB
• Plasma
• Fraxtal
• Zora
• Story
• Soneium
• Sei
• Hyperliquid
• Taiko
• Morph
• Ink
• Katana
• Ethereum Classic
• opBNB
• Flare
• Core
• Chiliz
• Telos EVM
• Tempo
• Cronos
• Manta Pacific
• Shibarium
• Boba Network
• Arbitrum Nova
• Immutable zkEVM

Frequently asked questions