Flashloan
Uncollateralised DeFi loan that must be taken and repaid within one atomic transaction. On TON it's implemented through sync-execution mode and is used in arbitrage and liquidations.
Aliases: flash loan
Flashloan is a loan with no collateral that must be taken and repaid within one atomic transaction. If repayment doesn’t happen, the entire transaction reverts (including the original disbursement). Because everything happens within one tx, the lender carries no risk.
Use cases
- Arbitrage between DEXes: take a flashloan, buy cheap on STON.fi, sell high on DeDust, repay the loan — profit is yours.
- Liquidations in lending protocols (EVAA): flashloan the funds, buy out an under-collateralised position, sell the collateral, repay, profit.
- Self-collateralised swaps: in advanced DeFi strategies.
TON-specific implementation
In EVM, a flashloan is trivially built on call → require(balance >= initial). On TON, where transactions are asynchronous, the implementation is harder: it uses sync-execution mode (single transaction with multiple operations) and BOUNCE-handling patterns. EVAA Protocol has supported flashloans for market-makers since 2025.
Risks of flashloan-enabled protocols
End users rarely use flashloan protocols directly. But they’re a top target for attackers: a flashloan can temporarily move price through a DEX pool and exploit price-oracle-dependent contracts.