Page Cache and Running Tests

While a test is running, targeted URLs miss full-page cache so WordPress can assign a variant and print its CSS, JS, or PHP on the first HTML response. Other URLs stay cached. Pause or complete the test to restore cache on those URLs.

This is different from cache-safe analytics. Analytics is designed not to bust HTML cache. A/B tests must vary HTML, so only the URLs you target are excluded, and only while the test runs.

What gets bypassed

• URLs that match the experiment’s effective page rules.
• The entire site if every URL rule is empty (treated as “all pages”).
• Broad rules such as all products, shop, a post type, or a wide regex — many URLs will miss cache. The editor warns you when targeting is broad.

Cache plugins

Alpha Insights registers exclusions for common stacks:

• WP Rocket — targeted paths are added to cache reject URIs while tests run.
• LiteSpeed — matching requests are marked no-cache.
• DONOTCACHEPAGE is set on matching front-end requests.
• A wpd_ai_experiment_bypass_cache action fires so other cache layers can opt in.

If you use Cloudflare, another CDN, or a host-level cache that ignores those hooks, add the same URL patterns as cache bypass rules for the duration of the test. Otherwise visitors may all see a cached control (or a cached treatment) and your results will be wrong.

Practical targeting

• Prefer a specific path (/pricing, a landing page, cart, checkout) over “entire site”.
• Do not leave empty path rules “for later” on a running test — empty rules mean site-wide.
• Pause immediately if you started with broad targeting by mistake.
• After you complete a test, purge cache once if your host keeps stale HTML.

Related

• Targeting and Audience
• Creating an A/B Test
• Cache-Safe Event Tracking