Flash Loan Simulator
Free to download on every platform. Comes pre-installed on BotFone, BotPad and BotFlip — with extra free apps included.
About this app
WHAT IT DOES
Flash Loan Simulator lets you test flash loan strategies before executing them on-chain. You provide the lending pool address, token address, loan amount, target contract, and calldata, and the tool simulates the execution to estimate profitability, gas costs, and risks. It calculates the flash loan fee (typically 0.09%), estimates gas usage, and determines whether the strategy would be profitable after fees and gas costs. This is essential for developers building arbitrage, liquidation, or refinancing strategies that rely on flash loans. It reads the current network chain ID from your wallet provider to ensure simulations are directed to the correct chain.
HOW TO USE
Connect your wallet using the "Connect" button (required for RPC access). Select the target network (Ethereum Mainnet, Sepolia, Polygon, BSC, Arbitrum, Optimism, and testnets are supported). Enter the flash loan parameters: lending pool address, token address, loan amount, target contract address, and calldata (hex). Click "Simulate flash loan" — the tool will estimate gas costs, calculate fees, and determine if the strategy is profitable. The entire operation is read-only — no transactions are signed or sent.
TECHNICAL MECHANISM
The tool simulates flash loan execution by estimating gas costs using provider.estimateGas and calculating the flash loan fee (based on the pool's fee structure). It evaluates the provided calldata and target contract to determine if the strategy would be profitable. The tool uses ethers.js v5.7.2 to interact with the chain via the wallet's provider. All calls are view functions — no state is modified. The tool does not execute the flash loan — it only simulates and reports potential outcomes.
WHAT IT CANNOT SEE
The tool cannot guarantee that simulated results will match actual on-chain execution due to state changes and gas fluctuations. It cannot account for slippage, MEV, or transaction ordering. It cannot detect all failure conditions without full execution context. It is limited by RPC provider simulation capabilities. It cannot execute the flash loan — only simulates and reports potential outcomes. It cannot simulate flash loans that require complex multi-step interactions or external dependencies.
PLEASE NOTE
This tool is for educational and research purposes. Always test flash loan strategies with small amounts before committing significant capital. The tool does not persist any data; all state is lost on page reload. EVM chains only.
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