Why is my website so slow despite optimization?

Technical Q&A

Topic summary

A Shopify store owner is experiencing severe desktop slowness despite optimizing images, removing apps, and using a free theme. Sales have declined, and customers have complained about the performance issue.

Root Cause Identified:

  • 504 server error discovered during inspection
  • Font request failures detected
  • Facebook sales channel app causing event request problems
  • Deleting the Facebook channel app improved speed, though the owner needs this functionality

Recommended Solutions:

Code & Assets:

  • Minimize HTTP requests and JS/CSS files
  • Implement critical CSS and reduce JS payload
  • Compress images further using tools like JPEGmini
  • Use lazy loading for images
  • Replace GIFs with static images

Infrastructure:

  • Consider upgrading to a paid, speed-optimized theme
  • Migrate tracking codes to Google Tag Manager
  • Preload web fonts and limit to one standard font
  • Use website monitoring tools

Technical Optimization:

  • Reduce page content size through pagination
  • Limit third-party scripts and Shopify apps
  • Implement AMP (Accelerated Mobile Pages)

The issue appears partially resolved after removing the problematic Facebook app, but a comprehensive optimization approach is still recommended.

Summarized with AI on November 21. AI used: claude-sonnet-4-5-20250929.
4

After inspecting the website I found this error:

Failed to load resource: the server responded with a status of 504 ()

and another error of font request failure.

Also there was an error with fbevents requests, so I ended up deleting Facebook sales channel app which is sad because I need it. Not sure if it was the source of the problem though, but seems like the website speed is better now!