Settings reference#

All settings live in one option, bb_cache_settings, edited under Settings → BB Cache. The keys and defaults below come from BB_Cache_Settings::defaults(); the descriptions follow the field help in inc/class-admin.php.

How values are stored#

Checkboxes are stored as 1 or 0. Numbers are cast to integers; cache_lifespan, lazyload_skip and cf_edge_ttl cannot be negative.
Lists are entered one item per line. Lines are trimmed, empty lines dropped and duplicates removed.
Choice fields fall back to their default when given an unknown value.
Every save posts all settings (the other tabs travel as hidden fields), rewrites config.php, writes or removes the .htaccess block and purges the page cache and the minified files.
Where a list accepts "substring or regex", an entry is first tried as a plain substring. It is also tried as a case-insensitive regular expression when it contains one of \ ( ) [ ] | * + ? ^ $. reject_uri and reject_ua are matched by the drop-in with their own rules, noted in their rows.

Some defaults were written for the site the plugin was built for. They are marked Site-specific default, review for your site.

Page cache#

Key	Default	What it does
`page_cache`	`1`	Stores the HTML of public pages under `wp-content/cache/bb-cache/pages` and serves it before WordPress loads.
`cache_lifespan`	`10`	Hours a cached file is valid. `0` keeps files until something purges them.
`cache_mobile`	`1`	Keeps a second file per URL for phone user agents.
`purge_all_on_update`	`0`	On: any post update purges everything. Off: purge the post, the home page, its archives and its parent only.
`preload_after_purge`	`0`	After a full purge, warm the cache from the sitemap in the background.
`cache_query_strings`	empty	Parameter names, one per line, that may be cached as separate variants. Pages with other parameters bypass the cache; marketing parameters (`utm_*`, `gclid`, `fbclid` and others) are ignored.
`reject_uri`	see below	URIs that are never cached. Each entry is matched as a substring and as a regex.
`reject_cookies`	see below	Cookie name prefixes. A request carrying a matching cookie is never served from or stored in the cache.
`reject_ua`	empty	User agents that are never cached. Each entry is a case-insensitive regex.
`htaccess_rules`	`0`	Writes an Apache rewrite block to `.htaccess` that serves cached files without starting PHP. Removed on deactivation. See Hosting notes.
`varnish_host`	empty	Host that receives `PURGE` requests mirroring each page-cache purge, for example `127.0.0.1`. Blank disables. See Hosting notes.

Default reject_uri:

/wp-json/
/feed/
/xmlrpc.php
/wp-login.php
/cart/
/checkout/
/my-account/

Default reject_cookies:

wordpress_logged_in_
wp-postpass_
comment_author
woocommerce_cart_hash
woocommerce_items_in_cart
wp_woocommerce_session_

Cloudflare#

Details in Cloudflare.

Key	Default	What it does
`cf_purge`	`0`	Mirrors every page-cache purge to the Cloudflare zone at the end of the request. Needs the zone ID and an API token.
`cf_zone`	empty	Zone ID, 32 hexadecimal characters. Overridden by the `BB_CACHE_CF_ZONE` constant.
`cf_token`	empty	API token with the permission Zone > Cache Purge > Purge. Overridden by the `BB_CACHE_CF_TOKEN` constant, which is the preferred place for it.
`cf_purge_mode`	`urls`	`urls` (Changed URLs): purge exactly the URLs the page cache purged. `all` (Everything): purge the whole zone on any purge.
`cf_edge_ttl`	`0`	Seconds the edge may hold public HTML, sent as `s-maxage`. `0` sends no edge headers.

File optimization#

Key	Default	What it does
`minify_css`	`1`	Removes comments and whitespace from local stylesheets; relative `url()` paths are made root-relative.
`concat_css`	`1`	Combines consecutive same-origin stylesheets into one file per page composition.
`exclude_css`	empty	Stylesheets to leave alone. Substring or regex of the URL.
`combine_google_fonts`	`1`	Merges multiple `fonts.googleapis.com` links into one with `display=swap`.
`minify_js`	`1`	Strips comments from local scripts. Newlines are kept; `.min.js` files are left as they are.
`concat_js`	`0`	Combines consecutive same-origin scripts with identical `defer` state into one file.
`exclude_js`	see below	Scripts to leave alone. Substring or regex of the URL or tag. Site-specific default, review for your site.
`optimize_logged_in`	`0`	Also run the optimisers for logged-in users. Off so editors see the raw page.

Default exclude_js (third-party script URLs used by the originating site; minify and combine only touch local files, so these entries have no effect on most sites and can be cleared):

fast.wistia.com/assets/external/E-v1.js
consent.cookiebot.com/uc.js
track.getgobot.com/gobot/js/pixel.js
assets.adoberesources.net/loader.js
static.claydar.com/init.v1.js

JavaScript#

Key	Default	What it does
`defer_js`	`0`	Adds `defer` to script tags with a `src`.
`exclude_defer_js`	see below	Scripts that are not deferred. jQuery is excluded because inline scripts use `$` immediately.
`delay_js`	`0`	Delays scripts until the first keypress, pointer movement, touch, click or wheel event, or the timeout below.
`delay_js_mode`	`thirdparty`	`thirdparty`: only scripts from other hosts and inline scripts that call them. `all`: every script except the exclusions.
`delay_js_timeout`	`5`	Seconds after which delayed scripts run without interaction. `0` means only on interaction.
`delay_js_exclusions`	see below	Scripts that are never delayed. Partly site-specific default, review for your site.

Default exclude_defer_js:

/jquery-?[0-9.]*(.min|.slim|.slim.min)?.js
code.jquery.com

Default delay_js_exclusions:

/jquery-?[0-9.](.*)(.min|.slim|.slim.min)?.js
code.jquery.com
js-(before|after)
(?:/wp-content/|/wp-includes/)(.*)
/forms2.min.js
mktoweb.com/js/forms2/js/forms2.min.js
consent.cookiebot.com
Cookiebot
speculationrules
application/ld+json

The jQuery, js-(before|after), /wp-content/ and /wp-includes/, speculationrules and application/ld+json entries are generic. The Marketo forms (forms2.min.js) and Cookiebot entries reflect the vendors the originating site used; keep them only if you use the same vendors, and add your own consent and form scripts.

Media#

Key	Default	What it does
`lazyload_images`	`0`	Adds `loading="lazy"` and `decoding="async"` to images. Images with `fetchpriority` or an existing `loading` attribute are untouched.
`lazyload_skip`	`2`	Leave the first N images eager. Images in the first screen stay eager regardless.
`lazyload_iframes`	`0`	Adds `loading="lazy"` to iframes.
`lazyload_youtube`	`0`	Replaces YouTube embeds with a click-to-play preview; the player loads on click.
`exclude_lazyload`	see below	Images and iframes that are never lazy-loaded. Substring or regex of the tag (class, file name). Site-specific default, review for your site.
`image_dimensions`	`0`	Adds missing `width` and `height` attributes to local images. Off by default because a theme that sizes images with `width:auto` and `object-fit` can show warped images once the attributes are present.

Default exclude_lazyload (class names and file names from the originating theme; they match nothing elsewhere and can be cleared):

caorusel-slide-img
promo-header__img
manage-pipelines-at-scale.png
single-logo
testimonial-slider--logo
g2-feb.png
gartner-feb.png

Boost#

Key	Default	What it does
`critical_css`	`0`	Inlines the page's critical CSS and loads every stylesheet asynchronously with a `<noscript>` fallback. Pages without critical CSS keep blocking stylesheets. See Critical CSS.
`critical_dir`	empty	Folder holding the critical CSS files. Blank means `<active theme>/assets/dist/css/critical`.
`critical_inline`	see below	Stylesheets inlined whole instead of loaded asynchronously, by substring or regex of the `href`, up to 24 KB each. Site-specific default, review for your site.
`host_google_fonts`	`0`	Fetches the Google Fonts CSS and font files once into `cache/bb-cache/fonts` and inlines the CSS with `font-display:swap`.
`cache_webp`	`0`	Swaps image URLs for a `.webp` sibling where one exists, for browsers that accept `image/webp`. Keeps a separate cache variant.
`lcp_preload`	`0`	Gives the first large, non-lazy image (or a hero background or video poster) `fetchpriority="high"` and a preload hint.
`exclude_lcp`	empty	Images never treated as the LCP image. Substring or regex of the tag or URL.
`lazy_videos`	`0`	Attaches `<video>` sources only when the video is near the viewport; the poster shows meanwhile.
`responsive_images`	`0`	Adds `srcset` and `sizes` to upload images the theme prints without them.
`auto_preconnect`	`0`	Adds `preconnect` hints for up to six third-party script and stylesheet hosts found on the page.
`html_minify`	`0`	Removes indentation, blank lines and comments. Whitespace between inline elements is not changed.
`content_visibility`	`0`	Adds `content-visibility: auto` to matching sections after the first N. Test with scroll-driven animations, which measure positions.
`content_visibility_selectors`	`content-section`	Class names, one per line, matched on `section`, `div`, `article` and `footer` elements. Site-specific default, review for your site.
`content_visibility_skip`	`2`	Leave the first N matching sections untouched.

Default critical_inline:

/css/pages/
/custom-css-js

/css/pages/ is the originating theme's folder of page-scoped stylesheets; /custom-css-js matches the files written by a custom CSS and JS plugin. Replace both with the paths of your own page-scoped sheets, or clear the list.

Preload#

Key	Default	What it does
`preload_links`	`1`	Prefetches same-origin pages when the pointer rests on a link (or on touch start). Disabled for visitors with data saver or a 2G connection.
`preload_cache`	`0`	Warms the page cache daily from the sitemap. Also available on demand from the admin bar, the Tools tab and WP-CLI.
`sitemap_url`	empty	Sitemap to read. Blank tries `/sitemap_index.xml`, `/sitemap.xml` and `/wp-sitemap.xml` and uses the first that answers `200`.
`dns_prefetch`	empty	Hosts to add as `dns-prefetch` hints, one per line.
`preconnect`	empty	Hosts to add as `preconnect` hints, one per line.
`preload_fonts`	empty	Font URLs to preload, one per line.

Heartbeat#

The three Heartbeat settings accept default (do not touch), reduce (every 2 minutes) or disable.

Key	Default	What it does
`heartbeat_admin`	`reduce`	Heartbeat on dashboard and admin pages.
`heartbeat_editor`	`reduce`	Heartbeat in the post editor (`post.php`, `post-new.php`, `site-editor.php`). Disabling it turns off autosave and post locking.
`heartbeat_front`	`reduce`	Heartbeat on the front end.
`disable_emoji`	`1`	Removes the WordPress emoji detection script and styles.

Tools tab#

The Tools tab holds no settings. It offers: purge all pages, clear minified CSS and JS (which also purges the pages), preload from the sitemap with its progress, reinstall the drop-in and set WP_CACHE, write or remove the .htaccess rules (with the block shown for manual pasting), the list of critical CSS files found, and the debug flags.