Download by Internet Download Manager is a Firefox extension designed to enhance the downloading experience by integrating directly with the popular Internet Download Manager. It operates in two distinct modes: users can either utilize context menu items to interact with various media elements like links, audio, video, and images or allow the extension to intercept downloads that would typically use the built-in browser manager, redirecting them to the external download manager. This flexibility caters to different user preferences and needs, making it a versatile tool for downloading tasks.

The extension is optimized for minimal resource usage, remaining inactive when the network observer is disabled. Users can customize when the external download manager is triggered based on specific criteria, such as file size, file type, and server capabilities. For proper functionality, the installation of a native client is required, which is supported on Windows, Linux, and Mac OS. This extension aims to provide a lightweight yet effective solution for managing downloads without unnecessary overhead.