VARNISH
Varnish is a high-performance HTTP accelerator for caching pages at the web server level. It is a freeware software with a free license, the installation of which can reduce the server load by hundreds of times.
The main purpose of Varnish is to redirect users to static pages. It is installed on port 80, which is used to communicate with the client via unencrypted HTTP, in front of your main NGINX or Apache web server. In the classic case, Varnish transmits to users what was previously stored in the cache. If there is nothing there, the accelerator sends a request to the designated backend server and stores its response. This approach speeds up delivery hundreds of times, regardless of the speed of the network itself. At the same time, both the overall download and the "time to first byte" are accelerated, which is good for keeping users on the site.
Varnish can be installed on almost all known Linux and Unix distributions. Any system you use can run faster.
Varnish can be easily customized to suit your project's specifics. Developers can set rules for processing incoming requests using the VCL language. For example, the accelerator does not cache requests if they have a cookie or an authentication header attached to them, as they affect how the page content is displayed. However, for static data, this restriction does not make sense and can be overridden. In addition, you can prevent large files, such as videos, from being stored in the cache, as well as set different storage times depending on the conditions, and much more.
Varnish Enterprise is a set of ready-made tools for working with an HTTP accelerator. A dedicated streaming server capable of processing 100 thousand requests per second, or a 5G-enabled cloud CDN, or maybe just a private content delivery network tailored to your project? Although Varnish itself is free software, there are ready-made saas products based on it, from different providers. You can choose a "service as a service" and pay to have everything working for you.
The second option is that your developers can write similar add-ons themselves or adapt ready-made ones published on GitHub, as well as find a comfortable hosting. It will definitely be beneficial to buy a subscription for those who make money on video streaming and use a lot of CDN servers. In all other cases, even if you have, for example, a large online store with review videos for each product, you can get by with basic Varnish.
Varnish is an add-on to your web server that will increase its performance. It's worth installing from the start if you're developing a high-load project and can be added to any web application as it scales. Varnish, as a cache, will reduce the load on the HTTP server and improve its performance.