This list includes:
- Online tools to test website speed
- Articles to interpret results
- Performance statistics
- Books on how to improve website performance
- CDN providers
Online tools to test your website performance:
- Webpagetest.org – is sponsored by Google, and is one of the most detailed free online tools. You can run tests from multiple geographic locations, on different browsers and different connection types. It gives you detailed metrics for Time to First Byte, Speed Index, Number of Requests, Load Time, Image compression, Caching, use of CDN, and more. In order to help understand the results, I recommend reading Beginner’s Guide to Waterfall Charts.
One of my favorite features is a Video Performance Comparison of several websites. Great way to compare your website speed to your competitors!
- GTMetrix – provides 2 scores, from Page Speed and YSlow, and provides very specific recommendations from both resources. It also gives you Page Load Time, Number of Requests and Total Page Size. GTMetrix shows a Waterfall chart that gives visualization of what resource takes the longest to load and how heavy is each resource. You can compare your site performance to your competitors. My favorite features are image optimization suggestions and performance alerts. You can download optimized images right from the results. You can also set up weekly or monthly email alerts, notifying you if page load time or page size goes up.
- Pingdom Website Speed Test – analyses website for speed and any bottlenecks. URL can be tested from 6 geographic locations. It provides a waterfall chart, number of requests, total load time, page size, and performance grade, page analysis and recommendations
- SpeedCurve.com – (Premium service) – continuous Performance and User Experience Monitoring. It gives you detailed analysis and film strips for your website. You can benchmark it to compare it against competitors. It provides weekly reports and alerts. It’s built on top of WebPagetest and you can share your dashboards with the team.
Performance related articles/tutorials:
I keep going back to these for reference
- Performance Calendar – Latest performance news/articles in chronological order
- Improving Smashing Magazine’s Performance: A Case Study – Very detailed article about how Smashing Magazine, a WordPress site dramatically improved their performance. This article has a lot of practical examples on render blocking scripts, defer loading of Web fonts, and optimizing the critical rendering path.
- More Weight Doesn’t Mean More Wait – Excellent article with practical examples about the value of Perceived performance and how to improve it.
- Beginner’s Guide to Waterfall Charts – Great read on how to create a waterfall chart, better understand reading it, and point out bottlenecks.
- Optimize Time to First Byte – One of my favorite articles understanding Time to First Byte. This article answers the following questions: What is Time to First Byte? How do you measure it? What affects it? What is latency? And most importantly, how do you improve it?
- HTTP/2 FAQ – detailed explanation of HTTP/2 protocol, what is the difference from HTTP/1 protocol, it’s benefits, how you can use it, and more
Gzip Compression, HTTP/2 Protocol Tests:
- Gzip compression – Check if your site is gzip enabled
- HTTP/2 test – Tests if your site supports HTTP/2 protocol
Website Performance Statistics:
- HTTPArchive – comprehensive repository of how Web is built, based on analyzing top 1,000,000 Top Alexa sites. You can view trends of website performance over the years. I particularly like Interesting Stats Page – that analyses an average website: how heavy it is, what resources take up the most space, average response time, number of requests, percentage use of custom fonts and more.
- WPO Stats – Case Studies, demonstrating the impact of Web Performance Optimization on User Experience and Business Metrics
Books about Web performance:
- Designing For Performance – written by Lara Hogan, lead performance engineer at Etsy.com. It’s a great book, easy to read. It discusses Page speed basics, best practices for optimizing and loading images, how to clean up CSS and HTML, using tools to measure performance as your site evolves, how to change your organization’s performance culture and more. All proceeds from the book sale go to charity.
- High Performance Browser Networking, written by Ilya Grigorik, web performance engineer at Google. It discusses optimization best practices, bottlenecks, as well as how to plan and deliver best performance for HTTP/2 protocol.
Related article: 10 ways to speed up your website
Are there any resources that you use that help optimize your website performance? Let me know in the comments