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Speculative Loading

By WordPress Performance Team

Performance & Optimization / Caching Solutions

Speculative Loading Review - In-Depth Analysis

This plugin enhances page loading speeds by enabling browsers to speculatively prerender or prefetch pages based on user interactions. It utilizes the Speculation Rules API for improved performance.

Performance Overview

WPS Score

6.63/10

User Rating

5/5 (based on 18+ reviews)

Active Installations

70,000+

Update Frequency

Below Average It is calculated using the weighted average of same category plugins.

Security Score

1 / 10 (Very Low Risk) It is calculated using the weighted average of all versions.

What It Does

This plugin adds support for the Speculation Rules API, which allows defining rules by which certain URLs are dynamically prefetched or prerendered. This core Speculative Loading functionality was merged into WordPress 6.8, but it only prefetches with conservative eagerness by default. In contrast, this plugin defaults to prerendering with moderate eagerness when interacting with a link, and it provides a user interface to customize the mode and eagerness via the Speculative Loading section on the Settings > Reading admin screen.

By default, speculative loading is only enabled for logged-out users, since unauthenticated pages are typically only eligible for caching and so more efficient to prefetch/prerender. This means that sites with frequent logged-in users on the frontend—such as e-commerce, forums, or membership sites—will not benefit from the feature. If your server can handle the additional load, you can opt in to enable speculative loading for all logged-in users or for administrators only. This setting exclusively affects frontend pages; admin screens are always excluded.

A filter can be used to exclude certain URL paths from being eligible for prefetching and prerendering. Alternatively, you can add the no-prerender CSS class to any link that should not be prerendered. See FAQ for more information.

The Speculation Rules API is a new web API, and the functionality used by the plugin is supported in Chromium-based browsers such as Chrome, Edge, or Opera using version 121 or above. Other browsers such as Safari and Firefox will ignore the functionality with no ill effects; they will simply not benefit from the speculative loading.

Comparing to Alternatives

Speculative Loading stands out among similar plugins by focusing on perceived speed improvements through intelligent resource loading strategies.

Top alternatives

Speculative Loading

Strengths

Significantly improves perceived page load times for users.
Proven compatibility with WordPress and WooCommerce sites.
Lightweight and efficient, causing no noticeable slowdowns.
Easy to install and configure with minimal setup required.

Weaknesses

Limited to speculative loading techniques without broader optimization features.
No official pro version or premium support options.
May not address all types of performance bottlenecks on complex sites.

User Sentiment Analysis

Users generally express strong satisfaction with Speculative Loading, highlighting its effectiveness and reliability.

Positive highlights

'Extremely fast and functional' - mrimpact
'Amazing results on install' - Hudson Atwell
'Substantially quicker than similar plugins' - groggy72
'Makes the site feel much faster to users' - lacoste89
'Works exactly as needed' - OllieJones

Common complaints

Weaknesses

No major complaints reported, but some users have yet to test on live heavy sites.
Lack of a paid version limits access to advanced features or dedicated support.

Who Should Use This?

Best for

Website owners and developers seeking a straightforward plugin to improve perceived loading speed without complex configuration.

Not ideal for

Users looking for comprehensive performance optimization suites or those requiring premium support and advanced features.

Pricing & Value

Free version includes

The free version offers all core speculative loading features, delivering noticeable speed improvements without cost.

Final Verdict

Speculative Loading is a highly effective plugin for enhancing perceived page load speed, praised for its simplicity and reliable performance across various WordPress setups.

While it lacks a pro version and advanced optimization features, its free offering provides excellent value for users wanting a quick and easy speed boost.

Other Notable Features

Here are a few other notable features of this free Speculative Loading plugin.

Javascript

Performance

Prefetch

Prerender

Speculation Rules

FAQ

Not every URL can be reasonably prerendered. Prerendering static content is typically reliable, however prerendering interactive content, such as a logout URL, can lead to issues. For this reason, certain WordPress core URLs such as /wp-login.php and /wp-admin/* are excluded from prefetching and prerendering. Additionally, any URLs generated with wp_nonce_url() (or which contains the _wpnonce query var) and nofollow links are also ignored. You can exclude additional URL patterns by using the plsr_speculation_rules_href_exclude_paths filter.

The following example ensures that URLs like https://example.com/cart/ or https://example.com/cart/foo are excluded from prefetching and prerendering:

<?php add_filter(     'plsr_speculation_rules_href_exclude_paths',     function ( array $exclude_paths ): array {         $exclude_paths[] = '/cart/*';         return $exclude_paths;     } );

Keep in mind that sometimes it may be useful to exclude a URL from prerendering while still allowing it to be prefetched. For example, a page with client-side JavaScript to update user state should probably not be prerendered, but it would be reasonable to prefetch.

For this purpose, the plsr_speculation_rules_href_exclude_paths filter receives the current mode (either “prefetch” or “prerender”) to provide conditional exclusions.

The following example ensures that URLs like https://example.com/products/... cannot be prerendered, while still allowing them to be prefetched:

<?php add_filter(     'plsr_speculation_rules_href_exclude_paths',     function ( array $exclude_paths, string $mode ): array {         if ( 'prerender' === $mode ) {             $exclude_paths[] = '/products/*';         }         return $exclude_paths;     },     10,     2 );

As mentioned above, adding the no-prerender CSS class to a link will prevent it from being prerendered (but not prefetched). Additionally, links with rel=nofollow will neither be prefetched nor prerendered because some plugins add this to non-idempotent links (e.g. add to cart); such links ideally should rather be buttons which trigger a POST request or at least they should use wp_nonce_url().

For safety reasons, the entire speculative loading feature is disabled by default for logged-in users and for sites that do not use pretty permalinks. The latter is the case because plugins often use URLs with custom query parameters to let users perform actions, and such URLs should not be speculatively loaded. For sites without pretty permalinks, it is impossible or at least extremely complex to differentiate between which query parameters are Core defaults and which query parameters are custom.

If you are running this plugin on a site without pretty permalinks and are confident that there are no custom query parameters in use that can cause state changes, you can opt in to enabling speculative loading via the plsr_enabled_without_pretty_permalinks filter:

<?php add_filter( 'plsr_enabled_without_pretty_permalinks', '__return_true' );

Contributors and developers

“Speculative Loading” is open source software. The following people have contributed to this plugin.

WordPress Performance Team

WordPress.org

Free Version

WPS

6.63

Average

Ratings

5 out of 5 | 18

Version

1.6.0

Last updated

3 months ago

Active installations

70,000+

WordPress version

7.0.4 or higher

PHP version

7.2 or higher

Languages

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Speculative Loading Review - In-Depth Analysis

Performance Overview

What It Does

Comparing to Alternatives

User Sentiment Analysis

Who Should Use This?

Pricing & Value

Final Verdict

Other Notable Features

FAQ

Contributors and developers

Ratings

Reviews (18)

Sort by:

Contributors & Developers

Interested in development?

Changelog

Security Status

Secure

No Unpatched Vulnerabilities

Known Vulnerabilities (0)

Previous Versions

WPS

6.63

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