Simulation

Dry-run any flash loan without spending SOL. Uses Solana's simulateTransaction with sigVerify: false to test against live on-chain state.

ℹ️ Note

Simulation uses instructions[] (not onFunds) — you pass your pre-built instructions directly.

Real-Time Fee Calculation

All fees displayed in the dashboard and returned by the API are calculated in real-time by the VAEA scanner. For synthetic routes, the scanner compares the fair market price (Jupiter Price API) against the actual execution price (Jupiter Quote) every 10 seconds.

Component	Method	Update Frequency
VAEA Fee	Fixed 3 bps (SDK) / 5 bps (UI)	Constant
Swap Cost (Direct)	None — borrowed directly	N/A
Swap Cost (Synthetic)	Price-vs-Quote: `1 - (quote_rate / fair_rate)`	~60s per token
Total Fee	VAEA fee + swap cost	Live

💡 Tip

The /v1/quote endpoint returns the exact fee breakdown for any token and amount. Use it to show users their real cost before execution.

Code Examples

Simulate a direct route (SOL) and a synthetic route (WIF) to see the fee difference:

// Direct route — fixed 0.03% fee
const solSim = await flash.simulate({
  token: 'SOL',
  amount: 5000,
  instructions: [myArbInstruction],
  slippageBps: 50,
  maxFeeBps: 15,  // fee guard: abort if fee > 0.15%
});

// Synthetic route — real-time fee from Jupiter quote
const wifSim = await flash.simulate({
  token: 'WIF',
  amount: 50000,
  instructions: [myArbInstruction],
  maxFeeBps: 30,  // higher guard for synthetic
});

if (solSim.success) {
  console.log('SOL simulation passed! CU:', solSim.computeUnits);
  console.log('Fee:', solSim.feeBreakdown.total_fee_pct, '%');
}
if (wifSim.success) {
  console.log('WIF simulation passed! CU:', wifSim.computeUnits);
  console.log('Fee:', wifSim.feeBreakdown.total_fee_pct, '%');
}

Response Schema

Field	Type	Description
`success`	`boolean`	Whether simulation passed successfully
`computeUnits`	`number`	Exact CU consumed — use to set compute budget
`feeBreakdown`	`FeeBreakdown`	Detailed fee: vaea_fee, swap_fee, total_fee_pct, total_fee_usd
`logs`	`string[]`	Full program execution logs
`error`	`string \| undefined`	Error details if simulation failed (JSON)

Use Cases

Strategy Testing

Validate new arb strategies against live state without risk

CU Estimation

Get exact compute units to optimize your compute budget request

Fee Verification

Confirm real-time fees match your profitability threshold before execution

CI/CD

Run simulated flash loans in your test suite on every commit

💡 Tip

The SDK automatically adds a 1.4M CU budget limit and uses replaceRecentBlockhash: true — no wallet signing required.