API Reference > imodeljs-frontend > Extensions > ExternalServerExtensionLoader ExternalServerExtensionLoader Class Beta Reads the extension from a plain server assuming that the extension is a set of files in a directory formatted as: "imjs_extensions//" if version is provided to ExternalServerExtensionLoader.loadExtension "imjs_extensions/" if version is not provided to ExternalServerExtensionLoader.loadExtension. Implements ExtensionLoader Methods Name Description constructor(serverName: string): ExternalServerExtensionLoader getExtensionName(extensionRoot: string): string loadExtension(extensionName: string, extensionVersion?: string, args?: string[]): Promise<undefined | PendingExtension> resolveResourceUrl(extensionName: string, relativeUrl: string): string Properties Name Type Description serverName string Defined in core/frontend/src/extension/loaders/ExternalServerExtensionLoader.ts Line 16 Last Updated: 29 November, 2022