simulateTransaction

Simulate a transaction against the current cluster state without submitting it.

Simulates a transaction against the current cluster state and returns the result, including any program logs. The transaction is never submitted to the network.

Request

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "simulateTransaction",
  "params": [
    "AQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAEEjNmKi...",
    { "encoding": "base64", "replaceRecentBlockhash": true }
  ]
}

Parameters

transaction · string · required

Signed or unsigned transaction, encoded as a base-58 or base-64 string.

encoding · string

Encoding of the transaction parameter. base58 or base64. Defaults to base58.

sigVerify · boolean

Whether to verify transaction signatures before simulating. Defaults to false. Cannot be used together with replaceRecentBlockhash.

commitment · string

Commitment level to use for the simulation. One of processed, confirmed, or finalized.

replaceRecentBlockhash · boolean

Replace the transaction’s recentBlockhash with the latest blockhash before simulating. Useful for simulating transactions without having to fetch a fresh blockhash first.

Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "context": { "slot": 393226680 },
    "value": {
      "err": null,
      "logs": [
        "Program 11111111111111111111111111111111 invoke [1]",
        "Program 11111111111111111111111111111111 success"
      ],
      "unitsConsumed": 1714,
      "returnData": null
    }
  }
}

value.err · object | null

null if the simulation succeeded. Contains the transaction error object if the simulation failed.

value.logs · string[]

Array of log messages produced by the programs invoked during the simulation.

value.unitsConsumed · number

Number of compute units consumed by the transaction.

value.returnData · object | null

Return data from the last program that set return data, or null.

value.accounts · array | null

Post-simulation account state, if requested via the accounts config option.

Example

cURL

curl "https://rpc.solami.fast/sol?api_key=YOUR_API_KEY" \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "simulateTransaction",
    "params": [
      "AQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAEEjNmKi...",
      { "encoding": "base64", "replaceRecentBlockhash": true }
    ]
  }'