Works with your stack
Cookie consent for Jetpack Boost
one cache file per cookie
Jetpack Boost merges and defers scripts, serves images from a CDN and has a page cache. Deferred scripts stay held. Merging, the image CDN and the cache key each have something to know.
By Automattic · jetpack.com · WordPress.org
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Jetpack Boost
WordPress plugin
- Tested version
- 4.8.2
- How
- Tested automatically around each Cookie Rocks version
- Last test
- 7 November 2026
- Latest version
- 4.8.2 tested
- Active installs
- 200,000+
What Jetpack Boost adds to your visitors’ browser
No trackers In our test of Jetpack Boost 4.8.2 on 7 November 2026, the plugin itself added no tracker and no cookie. What you place in your pages with it, such as a video or a map, still counts.
What matters for consent with Jetpack Boost
Merged scripts
With Concatenate JS on, Boost merges scripts into one file, so a held tracker could run before the choice. Cookie Rocks keeps held scripts out of the merge. Deferring only moves scripts to the end of the page, so held ones stay held.
The cache key reads cookies
Boost’s page cache keys on visitor cookies, so a consent cookie with a value per visitor creates one cache file per visitor after the choice. A developer can exclude it with Boost’s cookie filter, in a file loaded before plugins.
Images from Automattic
With Image CDN on, visitors’ browsers load your images from Automattic’s servers on every page. Name it in your cookie policy.
Cache cleared on save
The complete plugin empties Boost’s page cache when its settings are saved.
What our tests found on Jetpack Boost
Depends on a setting · Jetpack BoostJetpack Boost Concatenate JS can run held trackers before the choice
setting “Concatenate JS” · by default: off
With Concatenate JS on, Jetpack Boost merges enqueued scripts into one /_jb_static/ file, so a held tracker can run before the choice. Cookie Rocks 2.5.1 keeps held scripts out of the merge.
Seen in our tests, 17 October 2026, Jetpack Boost 4.8.1.
Good to know · Jetpack BoostCookie Rocks Pro empties Jetpack Boost's page cache on save
Cookie Rocks Pro empties Jetpack Boost's page cache (action jetpack_boost_clear_page_cache_all) when its settings are saved, as it does for other page caches.
Read in its code, 16 October 2026, Jetpack Boost 4.8.1.
Good to know · Jetpack BoostJetpack Boost's Defer JavaScript keeps held scripts held
setting “Defer Non-Essential JavaScript”
It moves scripts to the end of the page but does not change their type or wait for a gesture. It works outside the consent plugin, so held scripts stay held.
Read in its code, 16 October 2026, Jetpack Boost 4.8.1.
Full detail
Jetpack Boost's Defer Non-Essential JavaScript moves every script tag without data-jetpack-boost="ignore" to just before </body>, whatever its type, but does not change type or attributes and does not wait for a user gesture. Its output buffer opens at template_redirect priority -999999, outside the consent plugin's buffer, so scripts held as text/plain stay held.
Depends on a setting · Jetpack BoostJetpack Boost's Image CDN loads images from Automattic's servers
setting “Image CDN” · by default: off
Off by default. When on, images come from i0.wp.com on every page. Boost sets no visitor cookie; its Tracks script loads only for logged-in administrators.
Read in its code, 16 October 2026, Jetpack Boost 4.8.1.
Full detail
With Image CDN on (off by default), Jetpack Boost rewrites img tags to i0.wp.com (and i1, i2), so visitors' browsers load images from Automattic's servers on every page. Iframes are not touched. Boost itself sets no visitor cookie; the Tracks script is loaded only for logged-in administrators (Image Guide).
Good to know · Jetpack BoostJetpack Boost's page cache makes one copy per visitor with a consent cookie
Its cache key includes most visitor cookies, so a per-visitor consent cookie creates one cache file per visitor and page. The filter jetpack_boost_ignore_cookies goes in wp-content/boost-cache-extra.php.
Read in its code, 16 October 2026, Jetpack Boost 4.8.1.
Full detail
Jetpack Boost's page cache key includes the URL, GET parameters and all visitor cookies except a fixed list (Cloudflare, sbjs_*, _ga*, tk_ai, tk_qs...). A consent cookie with a per-visitor value therefore creates one cache file per visitor and page after the choice. The cookie filter jetpack_boost_ignore_cookies must be added in wp-content/boost-cache-extra.php, because the cache is served before plugins load. The first view without a cookie stays cached.
How we test it
Around each version, with its latest release
Around each Cookie Rocks version, a fresh WordPress installs its latest version from WordPress.org next to Cookie Rocks and runs the same checks. A new version joins the next run on its own.
- Jetpack Boost 4.8.2, tested on 7 November 2026.
- The banner shows, the trackers of the test page wait for consent and load after it, and Cookie Rocks raises no PHP error.
- Settings of the test: Default settings after activation.
- Last run: Jetpack Boost 4.8.2 on 7 November 2026, with WordPress 7.1.3.
Light as a pebble
11.43 kB once, 1.00 kB per page. Measured, not promised.
lighter than the font on this page*
Every kilobyte costs your visitors time and costs you Core Web Vitals. Cookie Rocks adds 11.43 kB to the first page a visitor opens, then 1.00 kB to each page after that, because its files stay in the browser cache. It calls no outside server and never shifts your layout.
11.43 kB First visit, in total
1.00 kB Each next page
7.74 kB JavaScript, first visit
3.48 kB Stylesheet, first visit
0 Requests to other servers
0 Layout shift caused
* The font on this page is Inter, compressed and cut down to the Latin alphabet. It still weighs 26.23 kB.
Page cache
Other plugins of the same kind.
Questions
What happens after the 30-day trial?
The banner, your visitors’ choices and your proofs of consent keep working. Without a key, most settings lock, updates and support stop. Take a key at any time and everything opens again.
For Jetpack Boost users
Boosted pages, consent first.
boost stays on
Every feature of the complete plugin for 30 days, no card. Jetpack Boost keeps working as it does today.
- During the trial: everything, including the full settings and the scans
- After 30 days without a key: the banner, your visitors’ choices and your proofs of consent keep working
- What waits for a key: most settings, updates and support
Get your trial key
Your e-mail and your site. Your key arrives as soon as you confirm your e-mail.