New technologies, WordPress · 2026.10.15

Speculative Loading in WordPress: What It Does

By Manu Mathew, Technical Lead Engineer · Published 15 October 2026 · Last updated 15 October 2026

You click a link on your own website and the next page appears almost at once. Nothing on the server changed, so what happened? On many sites, the answer is speculative loading in WordPress, a feature that has been switched on by default since WordPress 6.8.

It is quiet, it needs no setup, and most site owners never hear about it. That is mostly fine. But it does change what your server and your analytics see, and on a few kinds of sites it needs a quick check.

Quick answer

Speculative loading in WordPress asks the visitor’s browser to start fetching the next page as soon as they begin to click a link. It has been on by default since WordPress 6.8, for logged-out visitors on sites with pretty permalinks. Most small sites can leave it alone, but shops and sites with unusual links should test it.

What is speculative loading in WordPress?

It is a small set of instructions WordPress adds to each page, telling supporting browsers which links they may load early.

The instructions use a browser feature called the Speculation Rules API. WordPress writes a short block of rules into the page. The browser reads it and, when a visitor presses down on a matching link, starts loading that page a fraction of a second before the click finishes.

That fraction of a second is often enough to make the next page feel quicker. The WordPress core team’s announcement for 6.8 explains the default choices in detail.

By default, WordPress:

• Prefetches pages, which means it downloads the page’s HTML only.
• Uses conservative timing, so loading starts only when someone actually begins to click.
• Skips logged-in users, so you won’t see it while you’re signed in to your dashboard.
• Skips sites without pretty permalinks (addresses like /?p=123).
• Excludes admin pages, links with query strings, links marked nofollow and anything with the no-prefetch class.

What is the difference between prefetch and prerender?

Prefetch downloads the next page’s HTML; prerender goes further and builds the whole page out of sight, scripts and all.

WordPress chose prefetch with conservative timing because it is the safest setting to switch on for every WordPress site at once. Prerender gives a bigger gain, but it runs the next page’s JavaScript before the visitor sees it, which can upset badly written scripts.

Does speculative loading make my WordPress site faster?

It makes moving between pages feel faster, but it doesn’t speed up the first page a visitor lands on.

Speculative loading helps the second click, not the first impression. If your home page is slow from a search result, this won’t fix it.

Heavy images, too many plugins and slow hosting still matter more. I covered those in why your WordPress site is slow.

It also only works in browsers that support it. Chrome, Edge and other Chromium-based browsers do. Browsers without support simply ignore the rules, so nothing breaks for those visitors; they just don’t get the head start.

Can speculative loading cause problems?

Rarely with the default settings, but a few patterns deserve a check.

• Links that change something. A link that adds an item to a cart or logs someone out, using a plain URL, could in theory be fetched early. WordPress excludes links with query strings for this reason, and with conservative timing the visitor is about to click anyway.
• Analytics on prerendered pages. If you switch to prerender, a script that counts page views as soon as it loads may count pages nobody looked at. Most major analytics tools handle this already; older or custom scripts may not.
• Server load. Each early fetch is a real request. With the default timing that is close to normal traffic, but more eager settings mean more requests for pages that are never viewed.
• Content Security Policy. If your site has a strict security policy for scripts, the rules block may need explicit permission to run.

None of this means turning the feature off. It means knowing it is there when something looks odd in your logs or stats.

How do I check whether my site uses speculative loading?

Open any page while logged out, view the page source, and search for speculationrules.

1. Open your site in a private or incognito window, so you’re logged out.
2. Right-click the page and choose View page source.
3. Search the source for speculationrules.
4. If you find a <script type="speculationrules"> block, it is active. Look for prefetch or prerender, and conservative, moderate or eager, to see the current settings.

For a closer look, Chrome’s developer tools have a Speculative loads section in the Application panel. It lists which pages were loaded early and whether the browser used them.

Should I change the default settings?

For most small business sites, no: the default is a sensible, low-risk setting.

There are three good reasons to change it:

• To exclude certain pages. WordPress provides the no-prefetch and no-prerender CSS classes for blocks, and a developer filter for URL patterns such as a cart or account area.
• To go faster on a simple site. A content site with no shop and modern analytics may benefit from prerender or more eager timing. The WordPress performance team’s Speculative Loading plugin adds a settings screen for this.
• To fix a real conflict. If a plugin misbehaves because of early loading, exclude its pages rather than disabling the feature everywhere.

Change one thing at a time, and test it while logged out. Settings that look harmless on a blog can behave differently on a shop.

How I check speculative loading on a client site

When I review a WordPress site for speed, I treat speculative loading as part of the picture, not a separate project.

• I confirm it is on, and note the mode and timing in a short written summary.
• I look for risky links: plugin URLs that change state, logout links, language switches and cart actions that don’t use query strings.
• I check analytics and tracking, especially if anyone wants to move to prerender.
• I check the security policy, if the site sends one, so the rules aren’t silently blocked.
• I write down any change and the reason for it, with a simple way to undo it, before anything goes live.

Most of the time the result is a single line in the report: “Default speculative loading is on and working; no changes needed.” That is a perfectly good outcome.

Frequently asked questions

Do I need a plugin for speculative loading in WordPress?

No. Since WordPress 6.8, speculative loading is built into core and switched on by default for logged-out visitors on sites with pretty permalinks. A plugin is only useful if you want a settings screen to change the mode or timing without writing code.

Will speculative loading affect my SEO?

Not directly. Search engines don’t rank pages higher because the site uses speculation rules. It can make navigation feel faster for real visitors, which is good for them, but page content, links and the speed of the first page loaded still matter far more.

Why can’t I see speculative loading when I’m logged in?

WordPress turns it off for logged-in users by default. Admin and editing screens often contain links that change things, so it is safer not to load them early. Log out, or use a private window, to see what ordinary visitors get.

Does speculative loading use more bandwidth?

A little, with the default settings. Prefetch downloads only the HTML of a page the visitor has already started to click. More eager timing or prerender can load pages that are never viewed, so they use more bandwidth on both the server and the visitor’s connection.

Is it safe for a WooCommerce shop?

Usually, with the defaults, because links with query strings are excluded and loading starts only as a click begins. Before switching a shop to prerender or eager timing, test the cart, checkout, account pages and analytics while logged out, and exclude any pages that behave oddly.

Need a second pair of eyes on your site?

If you’d like someone to check your site’s speed settings, including speculative loading, I’m happy to look at it with you. You can read more about my WordPress website work, reach me through the contact section or email me at manu@manu.co.in. Tell me a little about your business and the site, and we’ll go from there.

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