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simulateTransaction

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simulateTransaction runs a transaction against the current bank state and returns the result it would produce if submitted, without ever broadcasting it. Use it to pre-flight a transaction: confirm it would succeed, read the program logs it would emit, measure the compute units it would consume, and inspect the post-execution state of selected accounts.

This is the right call before sendTransaction when you want to surface errors to the user, estimate a compute-unit budget, or decode a program's return data without paying fees. Because simulation reflects live bank state, the result is advisory — a transaction that simulates cleanly can still fail on submission if state changes in the interim.

By default the transaction's recent blockhash must be valid for simulation to succeed. Set replaceRecentBlockhash: true to have the node substitute the most recent blockhash before simulating, which lets you simulate a transaction whose own blockhash has already expired.

Tier note: this method belongs to the sol_sim_bundle category and is available on pro and business tiers only. Free- and basic-tier keys receive a -32002 tier-insufficient error.

Parameters

simulateTransaction parameters
NameTypeRequiredDescription
transactionstringYes
configSimulateTransactionConfigNo

Returns

simulateTransaction return value
FieldType
resultobject

Examples

curl https://triport.io/sol \
  -X POST -H 'Content-Type: application/json' \
  -H 'Authorization: Bearer <api-key>' \
  -d '{"id":1,"method":"simulateTransaction","params":["<transaction>","<config>"],"jsonrpc":"2.0"}'
const res = await fetch("https://triport.io/sol", {
  method: "POST",
  headers: { "Content-Type": "application/json", Authorization: "Bearer <api-key>" },
  body: JSON.stringify({
  "id": 1,
  "method": "simulateTransaction",
  "params": [
    "<transaction>",
    "<config>"
  ],
  "jsonrpc": "2.0"
}),
});
const data = await res.json();
import requests
resp = requests.post(
    "https://triport.io/sol",
    headers={"Authorization": "Bearer <api-key>"},
    json={"id":1,"method":"simulateTransaction","params":["<transaction>","<config>"],"jsonrpc":"2.0"},
)
print(resp.json())

Usage

  1. Transport: HTTP (JSON-RPC).
  2. Networks: mainnet, devnet, testnet.
  3. Credit cost: 5 per call.

FAQ

What does simulateTransaction do?
Simulates sending a Solana transaction without submitting it to the cluster, returning the would-be execution result, logs, and compute usage.
How many credits does simulateTransaction cost?
simulateTransaction costs 5 credit(s) per call on Triport by default.
Is simulateTransaction available over WebSocket?
simulateTransaction is an HTTP JSON-RPC method.