TriportRPC
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eth_callBundle

POSThttps://api.triport.io/

Simulates a Flashbots-style bundle of transactions against a chosen block **without submitting it**, returning the per-transaction execution results.

Ethereumeth_send_bundlepro (5 RPS) · business (15 RPS)

eth_callBundle runs an ordered list of signed, raw transactions as an atomic bundle against a target block and returns what each transaction would do — gas used, return value, and any revert — without broadcasting anything to the network. It is the dry-run companion to eth_sendBundle: use it to validate a bundle, estimate its coinbase payment, and confirm ordering before you commit real funds.

The bundle is simulated as if it were placed at the top of blockNumber, on top of the state at the end of stateBlockNumber. Because nothing is submitted, a successful response is not a guarantee of inclusion — it only tells you the outcome given the supplied state. Re-simulate against fresh blocks before sending, since mempool state moves every block.

This method is gated to the pro tier and above. Calls authenticated with a free-tier key are rejected with -32002.

Parameters

A single object passed as the first (and only) positional element of params.

txsstring[]required
Ordered list of signed, RLP-encoded raw transactions (each 0x-prefixed hex), simulated atomically in array order.
blockNumberstringrequired
Block number the bundle targets, as 0x-prefixed hex. The bundle is simulated as if included in this block.
stateBlockNumberstringoptional
Block tag or 0x-prefixed hex number whose post-state the simulation runs against (e.g. "latest"). Defaults to the block before blockNumber.
timestampnumberoptional
Unix timestamp (seconds) to use for the simulated block. Defaults to the expected timestamp of blockNumber.

Response

Response fields

FieldTypeDescription
bundleHashstringHash identifying the simulated bundle.
bundleGasPricestringEffective gas price across the bundle, in wei.
coinbaseDiffstringTotal wei the bundle would pay the block builder (gas fees + direct coinbase transfers).
ethSentToCoinbasestringWei sent directly to coinbase via transfers (excludes gas fees), in wei.
gasFeesstringTotal gas fees paid by the bundle, in wei.
stateBlockNumbernumberThe block number whose state the bundle was simulated against.
totalGasUsednumberSum of gas used across all transactions in the bundle.
resultsobject[]Per-transaction simulation results, in the same order as txs.
results[].txHashstringHash of the simulated transaction.
results[].gasUsednumberGas consumed by this transaction.
results[].gasPricestringEffective gas price for this transaction, in wei.
results[].gasFeesstringGas fees paid by this transaction, in wei.
results[].fromAddressstringSender address.
results[].toAddressstringRecipient / contract address.
results[].coinbaseDiffstringWei this transaction contributes to the builder.
results[].ethSentToCoinbasestringWei sent directly to coinbase by this transaction.
results[].valuestringReturn data of the call (0x-prefixed hex).
results[].error / results[].revertstringPresent only if the transaction failed; the revert reason or error string.

Errors

CodeMeaningWhen it happens
-32002tier_insufficientThe API key's tier is below pro; this method requires pro or business.
-32003rate_limitedRPS limit for your tier exceeded (pro: 5 RPS, business: 15 RPS).
-32602Invalid paramstxs missing/empty, malformed raw transaction, or invalid blockNumber.

All errors use the standard JSON-RPC envelope — see Errors for the full structure and retry guidance.

Examples

JavaScript (fetch)

const res = await fetch("https://api.triport.io/", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.TRIPORT_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    jsonrpc: "2.0",
    id: 1,
    method: "eth_callBundle",
    params: [
      {
        txs: [rawTx1, rawTx2],
        blockNumber: "0x1132a40",
        stateBlockNumber: "latest",
        timestamp: 1748476800,
      },
    ],
  }),
});


const { result } = await res.json();
console.log("coinbaseDiff:", result.coinbaseDiff);

TypeScript SDK (@triport/sdk)

import { Triport } from "@triport/sdk";


const client = new Triport({ apiKey: process.env.TRIPORT_API_KEY! });


const sim = await client.ethereum.callBundle({
  txs: [rawTx1, rawTx2],
  blockNumber: "0x1132a40",
  stateBlockNumber: "latest",
  timestamp: 1748476800,
});


console.log(sim.totalGasUsed, sim.coinbaseDiff);

Python (triport-sdk)

import os
from triport import Triport


client = Triport(api_key=os.environ["TRIPORT_API_KEY"])


sim = client.ethereum.call_bundle(
    txs=[raw_tx_1, raw_tx_2],
    block_number="0x1132a40",
    state_block_number="latest",
    timestamp=1748476800,
)


print(sim["totalGasUsed"], sim["coinbaseDiff"])

Notes

  • Simulation only. A successful response does not reserve a slot or guarantee inclusion. Submit with eth_sendBundle once the simulation looks correct, and re-simulate against the newest block first.
  • Atomic ordering. Transactions run in the exact order given in txs; a revert earlier in the bundle affects the state seen by later transactions.
  • stateBlockNumber accepts tags. Pass "latest" to simulate against current head state, or a specific hex block number for reproducible runs.
  • Wei strings. Monetary fields (coinbaseDiff, gasFees, bundleGasPrice) are decimal strings in wei to preserve precision.
  • Related: eth_sendBundle (submit a bundle for inclusion) — both share the eth_send_bundle scope and the pro/business tier gate.