> For the complete documentation index, see [llms.txt](https://calnix.gitbook.io/aave-book/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://calnix.gitbook.io/aave-book/functions/liquidate/validateliquidationcall.md).
# validateLiquidationCall
## Overview
### Execution flow
* [x] cache + updateState + get health factor
* [x] \_calculateDebt
* [ ] validateLiquidationCall
* [ ] getConfigurationData
* [ ] calculateAvailableCollateralToLiquidate
* [ ] setBorrowing
* [ ] setUsingAsCollateral
* [ ] \_burnDebtTokens
* [ ] updateInterestRates
* [ ] updateIsolatedDebtIfIsolated
* [ ] liquidate/burn collateral
* [ ] liquidation fee
* [ ] Wrap-up
## validateLiquidationCall
A valid liquidationCall must fulfil the following criteria:
* Status flags for both collateral and borrow asset must be ACTIVE and NOT PAUSED
* L2 check
* Ensure user's health factor < 1
* Collateral check
* check that liquidation threshold is non-zero
* confirm that user is using the collateral: `isUsingAsCollateral`
Since the liquidator can claim a single collateral of choice - we need to check the collateral address passed to ensure that it is indeed a valid selection. Else we might liquidate an asset that was not marked as collateral.
{% hint style="info" %}
**Liquidation threshold**
* is the percentage at which a loan is defined as under-collateralized.
* usually no more than 10-15% above LTV.
For example, a liquidation threshold of 80% means that if the loan value rises above 80% of the collateral, the loan could be liquidated.
If the loan reaches the liquidation threshold, Aave prevents a user from borrowing and the user must either partially close their position or provide more collateral.
{% endhint %}
A valid liquidationCall must fulfil the following criteria:
* Status flags for both collateral and borrow asset must be ACTIVE and NOT PAUSED
* L2 check
* Ensure user's health factor < 1
* Collateral check
* check that liquidation threshold is non-zero
* confirm that user is using the collateral: `isUsingAsCollateral`
Since the liquidator can claim a single collateral of choice - we need to check the collateral address passed to ensure that it is indeed a valid selection. Else we might liquidate an asset that was not marked as collateral.
{% hint style="info" %}
**Liquidation threshold**
* is the percentage at which a loan is defined as under-collateralized.
* usually no more than 10-15% above LTV.
For example, a liquidation threshold of 80% means that if the loan value rises above 80% of the collateral, the loan could be liquidated.
If the loan reaches the liquidation threshold, Aave prevents a user from borrowing and the user must either partially close their position or provide more collateral.
{% endhint %}