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Auditing Site Speed & Performance for eCommerce...

Sophie Gibson
March 11, 2025
Marketing & SEO
0
38

Auditing Site Speed & Performance for eCommerce Sites - WiTS x Sitebulb 2025

Webinar from the Women in Tech SEO x Sitebulb collaboration

🧠 What you’ll learn:

✔️ How to categorise issues into page templates
✔️ How to prioritise the issues based on how much they affect the site
✔️ Common issues and fixes required
✔️ Benchmarking data for fix impact reporting
✔️ How to analyze code coverage to improve site speed
✔️ Methods for testing proposed fixes to get buy-in from development teams

Sophie Gibson

March 11, 2025
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Transcript

  1. @sophiegibson @sagibson.co.uk studiohawk.co.uk Sophie Gibson Technical SEO Director at StudioHawk

    Account Management Auditing Site Speed & Performance

  2. @sophiegibson @sagibson.co.uk studiohawk.co.uk -

  3. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Challenges of performance testing ➔ Not

    developers ➔ Still have to advise on actions to fix issues ➔ Resource intensive ➔ Site size also impacts computing resources required

  4. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Why should we focus on site

    performance?

  5. @sophiegibson @sagibson.co.uk studiohawk.co.uk Source: Think with Google - Google/SOASTA Research,

    2017 https://www.thinkwithgoogle.com/intl/en-emea/marketing-strategies/app-and-mobile/mobile-page-speed-new-indu stry-benchmarks/

  6. @sophiegibson @sagibson.co.uk studiohawk.co.uk % Increase in conversions for every 100ms

    reduction in Largest Contentful Paint time 1.3 Source: https://web.dev/case-studies/farfetch

  7. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Setting the audit up for performance

    analysis

  8. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Audit Settings ✅ Use Audit Type:

    Sample ✅ In the Include & Exclude URLs tab, under Query String Parameters section, untick Crawl Parameters ✅ Turn on Performance & Mobile Friendly ✅ Under Advanced Settings, tick Code Coverage & untick Parse Technologies ✅ Under Web Vitals, select 25% - 50% of URLs, depending on site size

  9. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Audit Settings For Larger Sites ✅

    For larger or technically challenged websites, use URL List as the only source ✅ Manually identify URLs that match page template segments you’d like to analyse eg. collection pages, product pages, blog pages etc - around 20-40 examples of each should be sufficient ✅ Use Audit Type: Standard ✅ Under Web Vitals, select All URLs

  10. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Common Issues ✅ Scripts enabled on

    all pages, when only used on one specific template ➔ Location detection ➔ Google Maps ➔ Social embed code ✅ Bloated scripts that only use a small part of the code within it ✅ Font files which are not used on all pages or even used at all ✅ Images which are too large, or not lazy loaded in

  11. @sophiegibson @sagibson.co.uk studiohawk.co.uk - What to identify ✅ Page templates

    with the highest LCP / FCP ➔ Performance > HTML Templates ✅ Code that is unused, or partially used ➔ Code Coverage ✅ Data benchmarks for re-running crawls post fixes

  12. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Let’s demonstrate!

  13. @sophiegibson @sagibson.co.uk studiohawk.co.uk - now what?

  14. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Testing Fixes ✅ Using Resource Blocking

    ➔ DevTools ➔ Run Lighthouse test ➔ Network ➔ Right click on script identified in code coverage ➔ Block Request URL ➔ Re-run Lighthouse audit ➔ Use difference in scores to calculate conversion rate increase to calculate revenue difference for completing the fix

  15. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Testing Fixes ✅ Using Local Overrides

    ➔ DevTools ➔ Sources > Overrides ➔ Create folder & grant access ➔ Select Page Tab and select file to replace ➔ Right click & select Save for overrides ➔ Replace code by remove scripts or files identified for page template ➔ Save & reload page ➔ Re-run Lighthouse & record change Full instructions on my Where’s Your <head> At talk from BrightonSEO - Oct 2024

  16. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Prioritising Issues ✅ Focus on fixes

    on revenue driving page templates ✅ Prioritise performance issues that affect 100% of pages covered ✅ Prioritise fixes on page templates that have the highest Core Web Vitals metrics on average ✅ Use testing to calculate revenue metrics for the fixes, and prioritise high value issues

  17. @sophiegibson @sagibson.co.uk studiohawk.co.uk -

  18. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Direct Control Low Time / High

    Complexity - Requires your expert knowledge or a tool set-up - Larger scale / sitewide impact Dev Support High Time / High Complexity - Needs multiple sprints - More complex changes - Sitewide / large scale impact Direct Control Low Time / Low Complexity - Client able to action - Small scale / single page impact Dev Support High Time / Low Complexity - Larger in scale - Template level tweaks - Single line code changes Priority Matrix

  19. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Calculating Revenue Impact

  20. @sophiegibson @sagibson.co.uk studiohawk.co.uk Source: https://web.dev/case-studies/farfetch Before After 8.3s / 8300ms

  21. @sophiegibson @sagibson.co.uk studiohawk.co.uk % Increase in conversions for every 100ms

    reduction in Largest Contentful Paint time 1.3 Source: https://web.dev/case-studies/farfetch

  22. @sophiegibson @sagibson.co.uk studiohawk.co.uk 1.3% as a decimal is 0.013 &

    multiply by 83 1.079 Speed change in milliseconds 8300 Divide by 100 as Every 100ms = 1.3% increase 83

  23. @sophiegibson @sagibson.co.uk studiohawk.co.uk New conversion rate 2.08% Current conversion rate

    1% Fix would improve this by 1.079% 1.079% + =

  24. @sophiegibson @sagibson.co.uk studiohawk.co.uk £5700 at a £30 avg. order value,

    traffic that was worth

  25. @sophiegibson @sagibson.co.uk studiohawk.co.uk £11,85 is now worth

  26. @sophiegibson @sagibson.co.uk studiohawk.co.uk £6,150 this fix could increase revenue by

  27. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Recap

  28. @sophiegibson @sagibson.co.uk studiohawk.co.uk - Recap ✅ Determine the crawl settings

    required ✅ Use code coverage report to find scripts which are not used on the site at all, or waste code. ✅ Prioritise sitewide scale issues, and issues that cover 100% of a specific page template ✅ Test the impact of your changes using Local Overrides, or Resource Blocking within Dev Tools ✅ Calculate revenue impact to put together a business case for your technical tickets

  29. @sophiegibson @sagibson.co.uk studiohawk.co.uk Sophie Gibson Technical SEO Director at StudioHawk

    Thanks! @sophiegibson @studiohawk bsky.app/profile/sagibson.co.uk [email protected] linkedin.com/in/sophie-a-gibson/ ✉