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Simulates transaction execution against the current ledger state without committing anything on-chain. Returns success/failure, program logs, and any error details.
Simulation success does not guarantee on-chain success. If ledger state changes between simulation and submission (for example, another transaction modifies an account), the transaction may still fail.

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Request

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transaction
Transaction (object)
required
A compiled transaction (COMPILED state or later).
​
commitment_level
CommitmentLevel (enum)
Optional. Ledger state to simulate against. Defaults to CONFIRMED.
commitment_level is optional. When omitted or set to COMMITMENT_LEVEL_UNSPECIFIED, the service defaults to COMMITMENT_LEVEL_CONFIRMED. See CommitmentLevel for trade-offs between processed, confirmed, and finalized.

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Response

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success
bool
True if the simulation completed without errors.
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error
string
Error message if the simulation failed. Empty when success is true.
​
logs
string[]
Program execution log lines from the simulation run. Useful for debugging instruction failures.

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Code Examples

resp, err := client.SimulateTransaction(ctx, &transaction_v1.SimulateTransactionRequest{
    Transaction: compiledTxn,
})
if err != nil {
    log.Fatal(err)
}
if !resp.Success {
    fmt.Printf("Simulation failed: %s\n", resp.Error)
    for _, log := range resp.Logs {
        fmt.Println(log)
    }
}