PluginSift

Async JavaScript vs Speed Up – Optimize CSS Delivery (2026)

Detailed side-by-side comparison of two WordPress plugins, based on real-time data from WordPress.org.

Async JavaScript

Async JavaScript

4.7(102)

80K+ active installs

Free

Updated 2 years ago
View Async JavaScript
VS
Speed Up – Optimize CSS Delivery

Speed Up – Optimize CSS Delivery

5(8)

1.0K+ active installs

Free

Updated 3 years ago
View Speed Up – Optimize CSS Delivery

Quick Verdict

As of April 2026, Speed Up – Optimize CSS Delivery has a higher user rating (5/5 from 8 reviews) while Async JavaScript leads in active installations (80K+ vs 1.0K+). Both are free WordPress plugins. Async JavaScript has accumulated 2.0M+ total downloads while Speed Up – Optimize CSS Delivery has 59K+.

Detailed Comparison

Rating
4.7/5Async JavaScript
►
Speed Up – Optimize CSS Delivery5/5
Total Reviews
102Async JavaScript
◄
Speed Up – Optimize CSS Delivery8
Active Installs
80K+Async JavaScript
◄
Speed Up – Optimize CSS Delivery1.0K+
Total Downloads
2.0M+Async JavaScript
◄
Speed Up – Optimize CSS Delivery59K+
Support Resolution
N/AAsync JavaScript
Speed Up – Optimize CSS DeliveryN/A
Last Updated
2 years agoAsync JavaScript
◄
Speed Up – Optimize CSS Delivery3 years ago
First Released
2014Async JavaScript
Speed Up – Optimize CSS Delivery2016
Age
12 yearsAsync JavaScript
Speed Up – Optimize CSS Delivery10 years
WP Requires
4.6+Async JavaScript
Speed Up – Optimize CSS Delivery3.5+
PHP Requires
false+Async JavaScript
Speed Up – Optimize CSS Deliveryfalse+
Business Model
FreeAsync JavaScript
Speed Up – Optimize CSS DeliveryFree
Latest Version
2.21.08.31Async JavaScript
Speed Up – Optimize CSS Delivery1.0.11

Rating Breakdown

Async JavaScript

4.7/5(102 reviews)
5
88%
4
4%
3
1%
2
2%
1
5%

Speed Up – Optimize CSS Delivery

5/5(8 reviews)
5
100%
4
0%
3
0%
2
0%
1
0%

Recent Reviews

Async JavaScript Reviews

by lockbench

Great plugin

A truly great plugin, does exactly what is describing. No extra stuff, great implementation and great support! Thank you!

by gaiusjaugustus

Great plugin and support

I’ve been using this plugin for several months after it was suggested to me by a colleague. The setup was simple, but also gives advanced options that I needed, such as excluding certain scripts. I ha

by W★

Performance promise delivered

Exemplary support, and the plugin does exactly what it promises. This is unfortunately not a given in a time when many other plugins try to cover more and more tasks and end up in dangerous waters. As

Speed Up – Optimize CSS Delivery Reviews

by Wilson Santana

5 estrelas. Funciona muito bem.

Muito bom.

by mamadesign

This plug-in is a blessing

This plug-in is a blessing This plug-in is the best! We have to give a big prize to the person who created this plug-in. Thank you very much.

by castria

Works great!

Does what it says on the tin, which Google pagespeed likes a lot.

Frequently Asked Questions

Is Async JavaScript or Speed Up – Optimize CSS Delivery more popular?
Async JavaScript has 80K+ active installations while Speed Up – Optimize CSS Delivery has 1.0K+. Async JavaScript is the more widely-used plugin as of April 2026.
Which has better ratings — Async JavaScript or Speed Up – Optimize CSS Delivery?
Async JavaScript has a 4.7/5 rating from 102 reviews, while Speed Up – Optimize CSS Delivery has a 5/5 rating from 8 reviews.
Are Async JavaScript and Speed Up – Optimize CSS Delivery free?
Async JavaScript is free and Speed Up – Optimize CSS Delivery is free. Both can be downloaded from the WordPress.org plugin directory.
Which plugin has better support — Async JavaScript or Speed Up – Optimize CSS Delivery?
Support resolution data is not available for all plugins. Check each plugin's WordPress.org support forum for current response quality.
Which plugin is updated more frequently?
Async JavaScript was last updated 2 years ago and Speed Up – Optimize CSS Delivery was last updated 3 years ago.

Plugin data sourced from WordPress.org. Comparison and analysis by PluginSift.