How do online websites download youtube videos youtube?

There are several ways that online websites can download YouTube videos:

• Using the YouTube API: Many websites use the YouTube API (Application Programming Interface) to download videos from YouTube. The YouTube API allows developers to access certain features of the YouTube platform and build applications on top of it. However, using the YouTube API to download videos is generally not allowed by YouTube's terms of service.
• Web scraping: Some websites use web scraping techniques to download videos from YouTube. Web scraping involves using a program to send HTTP requests to a website's server and then parse the HTML or XML response to extract the data. Web scraping can be used to download videos from YouTube, but it is generally not allowed by YouTube's terms of service.
• Using a third-party downloader: There are several third-party programs and browser extensions that can be used to download videos from YouTube. These programs and extensions typically work by intercepting the video URL as it is being streamed from YouTube's servers and then downloading the video directly from the URL. Using third-party downloaders to download videos from YouTube is generally not allowed by YouTube's terms of service.

It is important to note that downloading videos from YouTube without the permission of the copyright holder is generally a violation of copyright law. There are some exceptions to this rule, such as fair use in the United States, but in general, it is best to avoid downloading videos from YouTube without the permission of the copyright holder.