> For clean Markdown content of this page, append .md to this URL. For the complete documentation index, see https://buildwithfern.com/learn/llms.txt. # Property names > Customize variable names for object properties using the `x-fern-property-name` extension The `x-fern-property-name` extension allows you to customize the variable name for object properties. For example, if you had a property called `_metadata` in your schema but you wanted the variable to be called `data` in your SDK you would do the following: ```yaml {6} components: schemas: MyUser: _metadata: type: object x-fern-property-name: data ``` > Customize variable names for object properties using the `x-fern-property-name` extension