FAQ

Is Speculatr really free?

Entirely, permanently, with no editions and no licence key. Every feature in this documentation is in the plugin you install.

Will this hammer my server?

It will increase requests, and how much depends entirely on the mode and eagerness you choose.

The honest framing: every speculation is a real request to your server for a page the reader has not asked for yet. At moderate eagerness that request happens after ~200 ms of hovering a link, so most of them are for pages somebody was about to open anyway. At eager or immediate, many more will be wasted.

Three things keep it bounded:

• Chrome holds only two speculations at a time at anything other than immediate.
• A prefetch is just the HTML — no images, no scripts, no subresources.
• Sec-Purpose is on every speculative request, so you can measure the real number before deciding it is a problem, and rate-limit or short-circuit at the edge if it is.

Start at prefetch + moderate if you are unsure. Move to prerender once you have looked at the traffic.

What is the difference between prefetch and prerender, really?

A prefetch downloads the page's HTML and puts it in a memory cache. Nothing on the page runs. It costs a few kilobytes and makes the eventual navigation noticeably faster.

A prerender loads and runs the entire page in a hidden tab — subresources, JavaScript, data fetches, everything — so that activating it is close to instant. It costs a full page load that may never be used, and it means your page's code executes before anybody clicked.

That second sentence is the whole reason this plugin is more than a snippet.

Does it track anybody?

No. Speculatr stores nothing, has no database tables, sets no cookies, and makes no outbound requests. It reads your Craft configuration and writes a JSON block into your pages.

Is speculative loading a privacy problem for my visitors?

It is worth being straight about. A prefetch or prerender is a real request, so your server logs a visit to a page the reader never opened, and any third-party script on a prerendered page may fire.

Two things mitigate it, and one is yours to do. Chrome sends Sec-Purpose on every such request so both you and your third parties can tell the difference. And a prerendered page is hidden, so anything correctly gated on the Page Visibility API — including Google Analytics 4 — holds off until the reader actually arrives. Your own counters need the craft.speculatr.isPrerender guard.

If your site is one where "which page did this person load" is itself sensitive, prefetch mode is the conservative choice: it never runs the page.

Does this affect GDPR or cookie consent?

It does not change what you collect, but it can change when scripts run. If you use a consent manager, check that it does not fire on a prerendered page before the reader has seen the banner — the same Page Visibility gating that fixes analytics applies here.

Speculatr itself has no consent implications: nothing to store, nothing to disclose.

Will it prerender my checkout, or sign people out?

Not by default, and that is the part of this plugin worth caring about.

Speculatr reads your Craft configuration and excludes the control panel, action requests (both by path and by ?action=), every login, logout and password path, and any URL carrying a preview, site or CSRF token — under whatever names your site gives them. A site that moved its control panel is covered without anybody remembering to say so.

The exception it cannot solve for you: a cart or checkout page with a URI of its own. Speculatr has no way to know you called it /basket. Add it to excludePaths. The Rules screen reminds you when Commerce is installed.

Does it work with full-page caching?

Yes, with one thing to get right. When a page fetched by a speculation is served without rules — the default — the response varies on the Sec-Purpose request header, and Speculatr sends Vary: Sec-Purpose to say so. If your CDN strips that, a rules-free copy can be cached and served to real visitors. See Troubleshooting.

Why do my prefetches miss when people arrive from a campaign link?

Because /pricing and /pricing?utm_source=newsletter are different URLs as far as the cache is concerned. ignoreTrackingParams fixes it by declaring — in a No-Vary-Search header and in the rules — that those parameters do not change the page. It is on by default.

Does it support Safari and Firefox?

No, because they do not support the Speculation Rules API. They ignore the block entirely, which costs their visitors a couple of kilobytes of JSON and nothing else. There is no fallback and none is wanted: a browser that does not speculate just loads the page when the reader clicks it.

Roughly two thirds of the web is Chromium, so this is a real improvement for most of your traffic and a no-op for the rest.

How is this different from a link-prefetch script like instant.page?

Those scripts listen for hover and inject <link rel="prefetch">. That works everywhere, and it is JavaScript you now ship and maintain.

Speculation Rules are declarative: the browser does the hover detection, applies its own limits and heuristics, and — crucially — can prerender, which no script can do. Speculatr also has the whole exclusion apparatus, which is the part a three-line script does not have and the part that eventually matters.

Does it work on multi-site installs?

Yes. Rules match the origin of the page they are on, so each site speculates its own links. The control panel's URL checker knows every origin your install serves.

Can I see what it is actually sending?

Speculatr → Rules in the control panel, or php craft speculatr/rules/show. Chrome's DevTools has an Application → Speculative loads panel that shows every rule, what it matched, and why anything was rejected.

What happens if I remove it?

Your pages go back to exactly what they were. There are no tables, no rows, and no residue — the plugin's entire output is a script element and two response headers, and both stop the moment it is uninstalled.