How to Use Flash Loans
Flash loans are uncollateralized loans that must be borrowed and repaid within a single transaction. If not repaid, the entire transaction reverts as if it never happened.
How Flash Loans Work
- Borrow any amount instantly
- Use funds within same transaction
- Repay principal + fee
- If repayment fails, entire tx reverts
| Use Case | Description |
|---|---|
| . . . . . | . . . . . . - |
| Arbitrage | Buy low, sell high across DEXs |
| Liquidations | Liquidate positions profitably |
| Collateral swap | Change position without unwinding |
| Self-liquidation | Avoid liquidation penalties |
Flash Loan Providers
- Aave: 0.09% fee
- Balancer: No fee
- Uniswap: 0.3% fee (via flash swaps)
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Step-by-Step Instructions
Understand Flash Loan Mechanics
Flash loans exist only within one transaction. Failure means nothing happens.
Tips
- ✓No collateral needed
- ✓Atomic: all or nothing
- ✓Must repay in same tx
Identify Use Case
Flash loans need profitable use: arbitrage, collateral swap, or liquidation.
Tips
- ✓Profit must exceed fees + gas
- ✓Arbitrage windows close quickly
Choose Tool or Build
Use Furucombo for no-code, DeFi Saver for position management, or code your own.
Tips
- ✓Furucombo: furucombo.app
- ✓No coding needed for basic uses
Test on Testnet
Always test flash loan logic on testnet first. One bug = failed transaction.
Warnings
- ⚠Failed tx still costs gas
- ⚠Test thoroughly before mainnet
Calculate Profitability
Include flash loan fee, gas costs, and slippage in profit calculation.
Tips
- ✓Aave fee: 0.09%
- ✓Gas on complex txs can be high
Execute Flash Loan
Run your flash loan transaction. Monitor for success.
Tips
- ✓High gas for priority
- ✓MEV protection recommended
Verify Results
Check your wallet for profit. Failed transactions show no change (except gas).
Tips
- ✓Success: check profit arrived
- ✓Failure: only lost gas