Web Operations

What Makes a Site Slow?

At the simplest level, web applications are slow because of three things:

• The time the server takes to process the client's request

• The time the network takes to transmit the request and response

• The time the client takes to assemble and display the resultant content

It's more complicated than this, of course, for several reasons:

Service Discovery

At the start of any web visit, the client needs to find the server. This is generally done by a DNS lookup, although the client may have cached the server's IP address. Additional steps may be involved in finding the right server, including HTTP redirects that send a client elsewhere.

Every time the client needs to get content from a new server, it has to go through this service discovery process. As a result, a website with many components—a pattern which is increasingly common online—forces clients to resolve many sites and takes longer to load the page.

Modern web design relies heavily on third-party components for payment, embedded videos, links to social media feeds, monitoring, and so on. Each additional component is another point of failure for you to worry about and another source of delay for visitors, robbing you of the advantage of a fast site.

Sending the Request

Networks can be only as fast as the round-trip time between the client and the server. Part of this is just physics: it takes light 13 milliseconds to get from New York to Las Vegas, and your data won't get there any sooner than that.^[20] The speed of ...