# GetExpressionBNFHash method

Gets a string hash calculated from the current Backus-Naur Form (BNF) grammar of the Qlik chart expressions supported within a given App.

Warning note**EXPERIMENTAL.**  
This API is under development. Do not rely on it. It may change or be removed in future versions.

## Returns

| Name | Description | Type |
| --- | --- | --- |
| qBnfHash | A string hash of the BNF definition. | String |

## See also

[GetExpressionBNFHash method](https://help.qlik.com/en-US/sense-developer/May2025/Subsystems/EngineJSONAPI/Content/service-Doc-GetExpressionBNFHash.htm)