Autoptimize

Item: Autoptimize
Rating: 4.7
Author: Fast WordPress

by Optimizing Matters

Aggregates and minifies CSS and JavaScript, inlines critical CSS and defers what is not needed for first paint.

4.71,428 WordPress.org reviewsPerformanceFree

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What Autoptimize does

Aggregates and minifies CSS and JavaScript, inlines critical CSS and defers what is not needed for first paint.

It sits in the performance part of a WordPress stack and is sold by Optimizing Matters on a free basis. We recommend it in our performance guides because it does that one job well without asking you to rebuild the rest of the site around it.

Every plugin adds work to a page request, so treat this as a decision with a cost. Record a speed test before you install it and run the same test afterwards, on the same page, so you know exactly what it charged you.

Real user ratings

Score

4.7/5

Reviews

1,428

Active installs

800,000+

Downloads

44.2M

Latest version

3.1.15.1

Last updated

2026-08-20

These figures come straight from the public WordPress.org plugin directory API for version 3.1.15.1, not from us. Check them yourself on the WordPress.org listing. Our own editorial score is 4.7/5.

Where Autoptimize ranks elsewhere

Autoptimize does not appear in the published "best of" lists we track from WPBeginner, TechRadar, Kinsta, Themeisle and similar sites. That is not a mark against it - those roundups are short and skew towards the biggest names.

What changed in the latest version

v3.1.15.1Latest release

fix for "Uncaught Error: Using $this when not in object context" when preloads are set

v3.1.15

also add fetchpriority=high to preload set on Extra tab
improve exit survey display in RTL languages
security enhancements for 2 authenticated stored XSS issues responsibly reported by stealhcopter and bashu
multiple minor changes/ improvements/ bugfixes, see the GitHub commit log .

v3.1.14

improve HTML output for <link rel="preload" images (based on report by Muhammad)
let the 404-handler issue a 302 iso 301 HTTP response (as mentioned by thefitrv)
small improvement in critical CSS cron job handling in case of an empty "time limit" (thanks for the help Jason)
fix bug in "domain binding" in critical CSS advanced options (reported by Hazel)
catch and report (exceptional) JS optimization issues causing preg_replace_callback to crash out (in case of a huge amount of JS code), thanks siliconforks
confirmed OK with WordPress 6.9

Release notes are the developer's own words, published on WordPress.org. Read the full changelog

Pros and cons

Free asset optimisation that pairs with any cache
Free with no licence to renew
Actively maintained and used on production sites we test

Aggressive settings can break themes, so test each toggle
Support is community-led rather than guaranteed

How to use it

1Record a baseline with our speed test before you change anything.
2Activate the plugin with its default settings and clear every cache layer.
3Re-run the test on the same page and template to see the real delta.
4Turn on one optimisation group at a time, testing after each change.
5Add exclusions for cart, checkout and logged-in pages.

How it compares

Other performance plugins we recommend, with their rating and pricing model.

Plugin	Our rating	WordPress.org	Pricing	Best for
Autoptimize	4.7	4.7 (1,428)	Free	Free asset optimisation that pairs with any cache
AMP	3.9	3.8 (367)	Free	Very fast mobile pages by construction
Breeze	3.6	3.6 (126)	Free	Works well on Cloudways servers with Varnish
Hummingbird	4.7	4.7 (1,487)	Freemium	The scan explains each fix in plain language
Jetpack	3.7	3.7 (2,407)	Freemium	One plugin replaces several smaller ones
WP Super Cache	4.3	4.3 (1,346)	Free	Simple, dependable static caching with no licence