mod_pagespeed Directive Index (Apache & nginx)

Every mod_pagespeed 1.15 directive is listed alphabetically below. In Apache, prefix each directive name with ModPagespeed (e.g., ModPagespeedEnableFilters). In nginx, prefix with pagespeed and terminate with a semicolon (e.g., pagespeed EnableFilters ...;).

Use this page for quick lookups. To see how directives fit together into a working setup, read the configuration reference; to turn individual optimizations on or off, see filter selection.

Directive	Default	Description	Docs
AddResourceHeader	(none)	Adds custom header to optimized resources	Configuration
AdminDomains	Allow *	ACL for admin page access	Admin Console
Allow	(none)	Allows optimization of resources matching a URL pattern	Domain Configuration
AdminPath	(none; IIS: /pagespeed_admin)	URL path for admin pages — unset means no handler on nginx/Apache	Admin Console
AutoCreateCachePath	on	Auto-creates the cache directory on first request (IIS)	IIS Configuration
AvifAnimatedRecompressionQuality	50	Quality for animated AVIF output	Image Filters
AvifQualityForSaveData	45	AVIF quality for clients sending Save-Data: on	Image Filters
AvifRecompressionQuality	60	AVIF quality level; -1 uses ImageRecompressionQuality	Image Filters
AvifRecompressionQualityForSmallScreens	50	AVIF quality for small-screen clients	Image Filters
AvifTimeoutMs	5000	Wall-clock budget for one AVIF encode; exceeded encodes are abandoned	Image Filters
CacheFlushFilename	cache.flush	Filename for legacy cache flush	Caching
CacheFlushPollIntervalSec	5	Interval to check for flush file	Caching
CacheFragment	(auto)	Cache partition key	Caching
ConsoleDomains	Allow *	ACL for console access	Admin Console
ConsolePath	(none; IIS: /pagespeed_console)	URL path for console — unset means no handler on nginx/Apache	Admin Console
CriticalImagesBeaconEnabled	on	Enables beacon for image optimization	Image Filters
CssFlattenMaxBytes	1024000	Max size for flattened CSS	CSS Filters
CssImageInlineMaxBytes	0	Max image size to inline in CSS	CSS Filters
CssInlineMaxBytes	2048	Max CSS file size to inline	CSS Filters
CssOutlineMinBytes	3000	Min inline CSS to externalize	CSS Filters
CycloneRamCacheKb	0 (r18+)	Cyclone RAM tier size (0 = off, -1 = legacy LRU coupling)	Caching
CycloneZeroCopy	off	Opt-in (r19+): read cached hits directly from the mapped cache file, no copy; the switch that opts a server into zero-copy serving	Caching
CycloneZeroCopyServe	on (needs CycloneZeroCopy)	Serve cached hits by reference (aliased) into the output buffer; engages only once CycloneZeroCopy maps values — set explicitly on Apache and IIS	Caching
DefaultSharedMemoryCacheKB	51200	Shared memory metadata cache size	Caching
Disallow	(none)	Prevents optimization of resources matching a URL pattern	Domain Configuration
DisableFilters	(none)	Disables specific filters	Filter Selection
DisableRewriteOnNoTransform	on	Honors Cache-Control: no-transform	Configuration
Domain	(none)	Authorizes a domain for resource fetching	Domain Configuration
EnableCachePurge	off	Enables per-URL cache purge	Caching
EnableFilters	(none)	Enables specific filters	Filter Selection
FetcherTimeoutMs	5000	Timeout for resource fetches	Caching
FetchHttps	enable	Controls HTTPS resource fetching	HTTPS Configuration
FetchWithGzip	off	Fetches resources with gzip Accept-Encoding	Caching
FileCachePath	(required)	Path for file-based cache storage	Caching
FileCacheSizeKb	1048576 (r18+)	Maximum file cache size in KB	Caching
FileCacheSmallTierPercent	10 (r18+)	Percent of cache reserved for metadata/page data (0=off)	Caching
ForbidAllDisabledFilters	off	Forbids all non-enabled filters	Filter Selection
ForbidFilters	(none)	Permanently disables specific filters	Filter Selection
GlobalAdminDomains	Allow *	ACL for global admin access	Admin Console
GlobalStatisticsDomains	Allow *	ACL for global statistics access	Admin Console
GlobalAdminPath	(none; IIS: /pagespeed_global_admin)	URL path for global admin — unset means no handler on nginx/Apache	Admin Console
GlobalStatisticsPath	(nginx path)	URL for global stats (nginx)	Admin Console
HonorCsp	on	Respects Content-Security-Policy headers and meta tags	Configuration
HttpCacheCompressionLevel	9	Compression level for cached HTTP responses	Caching
ImageInlineMaxBytes	3072	Max image size to inline as data URI	Image Filters
ImageLimitOptimizedPercent	100	Only serve if optimized is smaller	Image Filters
ImageLimitResizeAreaPercent	100	Only resize if result area is this percent of original	Image Filters
ImageMaxRewritesAtOnce	8	Parallel image optimization limit	Image Filters
ImageRecompressionQuality	85	Image recompression quality	Image Filters
ImageResolutionLimitBytes	33554432	Max image size to optimize	Image Filters
ImplicitCacheTtlMs	300000	Cache TTL for resources without explicit headers	Caching
InfoUrlsLocalOnly	on	Restricts admin/info URLs to the local machine (IIS)	Admin Console
InPlaceResourceOptimization	on	Enables IPRO	Caching
InPlaceRewriteDeadlineMs	10	IPRO rewrite deadline per flush	Caching
InPlaceSMaxAgeSec	10	s-maxage for IPRO responses	Caching
JpegRecompressionQuality	-1	JPEG quality (-1 = use general)	Image Filters
JsInlineMaxBytes	2048	Max JS file size to inline	JavaScript Filters
JsOutlineMinBytes	3000	Min inline JS to externalize	JavaScript Filters
LazyloadImagesMode	auto (r18+)	Lazy-loading mechanism: auto, native, or js	Image Filters
LazyloadImagesSkipFirst	1 (r18+)	Images at page start never lazy-loaded without fold data	Image Filters
ListOutstandingUrlsOnError	off	Shows fetch URLs in error responses	Configuration
LoadFromFile	(none)	Loads resources from filesystem	Domain Configuration
LoadFromFileCacheTtlMs	(ImplicitCacheTtlMs)	Cache TTL for filesystem-loaded resources	Caching
LogDir	(none)	Directory for statistics logging	Admin Console
LowercaseHtmlNames	off	Lowercases HTML tag/attribute names	Configuration
LRUCacheByteLimit	0	Legacy; no effect with the Cyclone backend	Caching
LRUCacheKbPerProcess	0	Legacy; sizes RAM tier when CycloneRamCacheKb is -1	Caching
MapOriginDomain	(none)	Maps public domain to origin for fetching	Domain Configuration
MapProxyDomain	(none)	Proxies and optimizes content from a separate origin	Domain Configuration
MapRewriteDomain	(none)	Rewrites resource URLs to another domain	Domain Configuration
MaxSegmentLength	1024	Max length of a generated URL segment	Configuration
MemcachedServers	(none)	Memcached server list	Caching
MemcachedTimeoutUs	500000	Memcached operation timeout	Caching
MessageBufferSize	0	Size of message history buffer	Admin Console
MessagesDomains	Allow *	ACL for message history	Admin Console
MessagesPath	(nginx path)	URL for messages (nginx)	Admin Console
ModifyCachingHeaders	on	Sets caching headers on HTML	Configuration
NativeFetcherMaxKeepaliveRequests	100	Max requests per keepalive connection for the native fetcher (nginx, http block only)	HTTPS Configuration
PreserveUrlRelativity	on	Preserves relative URLs	Configuration
PurgeMethod	(none)	HTTP method for cache purge	Caching
RateLimitBackgroundFetches	on	Rate-limits background fetches	Caching
RedisDatabaseIndex	0	Redis database index	Caching
RedisReconnectionDelayMs	1000	Redis reconnection delay	Caching
RedisServer	(none)	Redis server address	Caching
RedisTimeoutUs	50000	Redis operation timeout	Caching
RedisTTLSec	-1	Redis entry TTL	Caching
RespectVary	off	Respects Vary headers on resources	Configuration
ResponsiveImageDensities	1.5,2,3	Pixel densities generated for responsive_images	Image Filters
RetainComment	(none)	Wildcard pattern for comments to keep	HTML Filters
RewriteDeadlinePerFlushMs	10	Rewrite timeout per HTML flush	Caching
RewriteLevel	CoreFilters	Baseline filter set	Filter Selection
RewriteRandomDropPercentage	0	Random percentage of rewrites to skip	Filter Selection
ShardDomain	(none)	Distributes resources across domains	Domain Configuration
ShmMetadataCacheCheckpointIntervalSec	300	No-op; superseded by write-through (v1.15.0+r17)	Caching
SslCertDirectory	(none)	SSL certificate directory	HTTPS Configuration
SslCertFile	(none)	SSL certificate file	HTTPS Configuration
StaticAssetPrefix	/pagespeed_static/	URL prefix for static assets	Configuration
Statistics	on	Enables statistics collection	Admin Console
StatisticsDomains	Allow *	ACL for statistics access	Admin Console
StatisticsLogging	off	Enables logging for console graphs	Admin Console
StatisticsPath	(nginx path)	URL for statistics (nginx)	Admin Console
SupportNoScriptEnabled	on	Inserts noscript redirect	Troubleshooting
UseNativeFetcher	off	Uses nginx’s event-driven fetcher for resource fetches, HTTP and HTTPS (nginx, http block only)	HTTPS Configuration
UsePerVhostStatistics	off	Per-virtual-host statistics	Admin Console
WebpAnimatedRecompressionQuality	70	Quality for animated WebP conversion	Image Filters
WebpRecompressionQuality	80	WebP quality level	Image Filters
XHeaderValue	(version)	X-Mod-Pagespeed/X-Page-Speed header value	Configuration

See also

• Configuration — general configuration reference
• Filter Selection — filter enable/disable directives
• PageSpeed markers reference — the attributes and headers these directives produce at runtime