# GetExpressionBNF method

Gets 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 |
| --- | --- | --- |
| qBnfDefs | Description of the scripting language grammar. | Array of [BNFDef](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/EngineJSONAPI/Content/models-bnfdef.htm) |
| qBnfHash | A string hash of the BNF definition. | String |

## See also

[GetExpressionBNF method](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/EngineJSONAPI/Content/service-Doc-GetExpressionBNF.htm)