Perfmatters Baseline
Perfmatters helps you remove unnecessary WordPress features and manage assets so your pages ship less CSS/JS and do less background work. This page gives you a baseline configuration and a repeatable way to verify the change actually improved performance (without breaking functionality).
caution
Apply changes on staging first. Turn on one group of settings at a time, purge caches, and re-test critical routes (checkout, forms, login, search).
Baseline Workflow
- Record a baseline (PageSpeed Insights + DevTools Network) on a few representative URLs.
- Enable the "safe" cleanup toggles.
- Purge page/server/CDN caches and re-test.
- Only then consider more aggressive features (Delay JS, Remove Unused CSS).
Safe Baseline Toggles
These are commonly safe for most sites, but still validate on your templates.
| Setting (Perfmatters) | Recommendation | Notes |
|---|---|---|
| Disable Emojis | On | Removes wp-emoji-release.min.js. |
| Disable Embeds | On | Removes wp-embed.min.js. |
| Remove jQuery Migrate | On | Can break legacy themes/plugins; verify front-end behavior. |
| Remove RSD / WLW / shortlinks | On | Cleanup/hardening; usually low risk. |
| Disable Dashicons (front-end) | Depends | Safe if you don't show the admin bar to logged-in users. |
| Heartbeat | Reduce | Prefer reducing frequency over disabling entirely. |
| XML-RPC | On (if unused) | Hardening; confirm nothing relies on it. |
Settings That Depend on the Site
| Setting | Use When | Watch Out For |
|---|---|---|
| Disable REST API | Rare | Can break WooCommerce, block editor features, and many plugins. |
| Delay JavaScript | When INP/JS is the bottleneck | Can break checkout, sliders, menus, and analytics if misconfigured. |
| Remove Unused CSS | When CSS is heavy and stable | Can cause layout breakage or CLS if not tested thoroughly. |
Verify the Change
After enabling baseline toggles and purging cache, verify that the expected scripts no longer load.
expected-removed-assets.txt
/wp-includes/js/wp-emoji-release.min.js
/wp-embed.min.js
/wp-includes/js/jquery/jquery-migrate.min.js
Also re-run PageSpeed Insights and compare the same metrics/URL (TTFB, LCP, CLS, INP) using the same test strategy.
Common Pitfalls
- Delay JS breaks interactive features: add exclusions for critical scripts and re-test.
- Disabling REST API breaks dynamic flows: avoid on WooCommerce/LMS/membership sites.
- Changes appear to do nothing because of cache: purge server cache and CDN cache before comparing.