The transaction must repay or return the assets before it ends; otherwise every state change reverts.
No upfront collateral does not mean no constraints: fees, liquidity, gas and executable profit remain.
Key takeaways
- Assets arrive before payment. The pool invokes a callback in the borrower contract.
- Atomicity enforces repayment. Failure reverses the whole transaction.
- Profit must exceed every cost. Price impact, fees, gas and MEV reduce the edge.
- Callbacks expand attack surface. Authentication and reentrancy controls are essential.
A simple arbitrage
Borrow an asset from one pool, sell it where the price is higher, acquire what the first pool requires and repay plus fee. The borrower keeps only the remainder.
Why users still lose
A public transaction can be copied or sandwiched, state can change before inclusion and a calculation error can consume gas even when the swap reverts.
Developer controls
Validate the pool caller, bound slippage and profit, use current reserves, handle token quirks and test adversarial ordering on a fork.
Decision checklist
Verify current official documentation, contracts or legal entities, administrator permissions, fees, liquidity and the full exit path. Test the smallest practical transaction and record what happens when an interface, oracle, bridge, operator or counterparty fails.
Keep a dated baseline of addresses, reserves or collateral, governance roles and normal withdrawal results. Recheck it after upgrades or incidents. An audit, license application, partnership or TVL number answers only one part of the risk.
Before increasing exposure, define an observable stop condition: a collateral deviation, missed withdrawal, governance change, loss of market depth or unsupported software version. Decide the response in advance and retain enough native gas and independent wallet access to execute it without relying on customer support.
Crynet turns complex products into evidence-led market communication through Web3 strategy and execution.
This article is educational and is not financial, legal or investment advice.
