# Flex > Flex file localization URL: https://store.crowdin.com/flex Category: File Formats Type: System Author: Crowdin Flex is a natively supported file format, you can use it without an additional installation. Just upload it to your projects and start the localization. ## File Format Details | Attribute | Value | | --------- | ----- | | File Extension | .properties | | [API Type](https://developer.crowdin.com/api/v2/#operation/api.projects.files.post) | flex | | Source can be edited in Crowdin | No | | Generating translated files via [Bundles](https://support.crowdin.com/bundles/) | [Search Crowdin Store](https://store.crowdin.com/tags/string-exporter) | | Supports pluralization | No | | WYSIWYG Preview in the editor | No | | Supported types of contextual information | Text comments, Screenshots | | Custom attributes | No | | Existing translations import possibility | Key-value mapping | ## Sample File ```ini # locale/en_US/RegistrationForm.properties welcome_message=Welcome! save_as_button=Save as... view=View about=About... about_me=About Me current_password=Current Password ``` ## Translating Flex **Note**: To upload Flex, use API or CLI specifying the localization type: “flex”