| AddResourceOptions | Options for adding a single resource entry. |
| Callback | Callback type for i18next operations. |
| GetResourceOptions | Options for getting a single resource value. |
| HasLoadedNamespaceOptions | Options for checking whether a namespace has been loaded. |
| I18n | Main i18next instance interface. |
| I18nModules | Container for loaded i18next plugin modules. |
| InitOptions | Configuration options for initializing i18next. |
| InterpolationOptions | Options for configuring i18next string interpolation. |
| Module | An i18next plugin module. |
| ModuleConstructor | Constructor for an i18next module. |
| ResourceStore | Store for managing i18next translation resources. |
| Services | Container for i18next service instances. |
| TFunction | Translation function type for i18next. |