WebPageTest Staff

Tim Kadlec

Tim Kadlec is the Director of Engineering for WebPageTest, a web performance consultant, and trainer focused on building a web everyone can use. He is the author of High Performance Images (O'Reilly, 2016) and Implementing Responsive Design: Building sites for an anywhere, everywhere web (New Riders, 2012). He writes about all things web at timkadlec.com.

All posts by Tim Kadlec

1. 

   Feb. 09, 2023 - 4 min. Read

   Better Performance Testing Through the Power of Defaults

   

   Tim Kadlec

   • How We Built It
   • Browsers
   • Connections
   • Locations
   • Settings
2. 

   Jan. 19, 2023 - 4 min. Read

   WebPageTest's Guiding Principles

   

   Tim Kadlec

   • How We Built It
   • Opportunities
   • Experiments
   • Locations
3. 

   Oct. 04, 2022 - 4 min. Read

   September 2022 WebPageTest Roundup

   

   Tim Kadlec

   • WebPageTest News
   • Experiments
   • TTFB
   • API
   • Chrome
   • Scripting
   • Integrations
4. 

   Sep. 20, 2022 - 5 min. Read

   No More EV Certificate Overhead in Chrome 106

   

   Tim Kadlec

   • Optimizations
   • SSL
   • Chrome
   • Metrics
5. 

   Aug. 18, 2022 - 3 min. Read

   Improving Paint Metrics by Removing Unused Preloads

   

   Tim Kadlec

   • Optimizations
   • Largest-Contentful-Paint
   • Start-Render
   • Preload
   • Experiments
6. 

   Aug. 11, 2022 - 3 min. Read

   Introducing the New WebPageTest Recorder Chrome Extension

   

   Tim Kadlec

   • WebPageTest News
   • Chrome
   • Scripting
   • Integrations
7. 

   Jun. 01, 2022 - 5 min. Read

   Introducing Opportunities & Experiments: Taking the Guesswork out of Performance

   

   Tim Kadlec

   • WebPageTest News
   • Opportunities
   • Experiments
8. 

   Feb. 17, 2022 - 4 min. Read

   January WebPageTest Roundup

   

   Tim Kadlec

   • WebPageTest News
   • API
   • Core Web Vitals
   • JavaScript
9. 

   Jan. 27, 2022 - 3 min. Read

   Unveiling the new WebPageTest UI

   

   Tim Kadlec

   • WebPageTest News
10. 

    Oct. 07, 2021 - 3 min. Read

    September WebPageTest Roundup

    

    Tim Kadlec

    • WebPageTest News
    • API
    • Metrics
    • Chrome
    • TTFB
    • ElementTiming
11. 

    Sep. 22, 2021 - 5 min. Read

    Full Throttle: Comparing packet-level and DevTools throttling

    

    Tim Kadlec

    • Perf Data
    • Render-Blocking
    • Throttling
12. 

    Sep. 08, 2021 - 3 min. Read

    August WebPageTest Roundup

    

    Tim Kadlec

    • WebPageTest News
    • API
    • Render-Blocking
    • NodeJS
    • Documentation
13. 

    Aug. 12, 2021 - 2 min. Read

    Announcing Official Support for the WebPageTest API Wrapper for NodeJS

    

    Tim Kadlec

    • WebPageTest News
    • API
    • NodeJS
14. 

    Aug. 05, 2021 - 3 min. Read

    July WebPageTest Roundup

    

    Tim Kadlec

    • WebPageTest News
    • VS Code
    • Render-Blocking
    • CSS
    • JavaScript
    • Critical Path
15. 

    Jul. 20, 2021 - 4 min. Read

    New Render Blocking Indicator in Chrome and WebPageTest

    

    Tim Kadlec

    • WebPageTest News
    • JavaScript
    • CSS
    • Render-Blocking
    • Critical Path
16. 

    Jul. 08, 2021 - 2 min. Read

    June WebPageTest Roundup

    

    Tim Kadlec

    • WebPageTest News
17. 

    Jun. 15, 2021 - 9 min. Read

    Benchmarking JavaScript Memory Usage

    

    Tim Kadlec

    • Perf Data
    • JavaScript
    • Chrome
    • Metrics
    • Memory
18. 

    Jun. 09, 2021 - 3 min. Read

    May WebPageTest Roundup

    

    Tim Kadlec

    • WebPageTest News
19. 

    May. 04, 2021 - 6 min. Read

    Why First Contentful Paint Doesn't Work As a Cross-Browser Metric

    

    Tim Kadlec

    • Perf Data
    • First Contentful Paint
    • Core Web Vitals
    • Safari
    • Chrome
    • Firefox
20. 

    Apr. 27, 2021 - 3 min. Read

    Extending WebPageTest with Custom Metrics

    

    Tim Kadlec

    • WebPageTest News
    • custom metrics
    • accessibility
    • API
    • lazy loading
21. 

    Apr. 13, 2021 - 9 min. Read

    Diving Into the New Cumulative Layout Shift

    

    Tim Kadlec

    • Perf Data
    • CLS
    • CrUX
    • Core Web Vitals
22. 

    Apr. 06, 2021 - 6 min. Read

    Automatic WebPageTest Results for Every Docs Deploy

    

    Tim Kadlec

    • How We Built It
    • API Integration
    • GitHub
    • Eleventy
    • Netlify
23. 

    Jan. 28, 2021 - 4 min. Read

    With M1 Mac Minis, The Future is Bright for Mobile Device Testing

    

    Tim Kadlec

    • WebPageTest News
    • M1 Mac Mini
    • Mobile Testing
    • Safari