Analysis of website performance is something that should be done regularly by every responsible web-site developer. One method to troubleshoot and find out the reason for slow work is diving into web-site’s requests. It is called “waterfall analysis”. There are different free tools in the Net that will create a waterfall chart for you: Chrome DevTools, WebPageTest, or Pingdom. If you comprehend how they work, you will have a great insight into how assets on you web-pages are transfer, and what user’s experience is like.
In the beginning, all these lines and bars of different colors can be confusing, but as soon as you start differentiating the pieces of the chart, it will be quite easy to analyze. And keep in mind that names of these attributes can slightly vary depending on the tool you use. So what does waterfall analysis show?
- DNS Lookup / DNS
- Initial Connection / Connect
- SSL negotiation (time to perform SSL handshake)
- TTFB / Waiting
- Content Download
- DOM (Document Object Model) content loading
- Load Time / Fully Loaded – the total time for a webpage to load
- Data Transferred (also may be called as bytes in or page size)
- Number of HTTP Requests
- Status Codes / Error / Server Response Codes are messages that show completion of data transfer (200 or 404)
Above-mentioned tools can provide you with various sorts of statistics concerning how pages are loading, and what can cause delays. When you understand what each aspect on the graph means, you will troubleshoot better and understand what can be improved in your website. All of these variables can be influenced and optimized using CDN services.