Improve site performance and user experience via caching: browser, page, object, database, minify and content delivery network support.
|Author:||Frederick Townes (profile at wordpress.org)|
|WordPress version required:||3.2|
|WordPress version tested:||5.0.3|
|Added to WordPress repository:||29-07-2009|
|Total downloads:||13 545 950|
|Active installs:||1 000 000+|
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Why does speed matter?
Search engines like Google, measure and factor in the speed of web sites in their ranking algorithm. When they recommend a site they want to make sure users find what they’re looking for quickly. So in effect you and Google should have the same objective.
Speed is among the most significant success factors web sites face. In fact, your site’s speed directly affects your income (revenue) — it’s a fact. Some high traffic sites conducted research and uncovered the following:
- Google.com: +500 ms (speed decrease) -> -20% traffic loss 
- Yahoo.com: +400 ms (speed decrease) -> -5-9% full-page traffic loss (visitor left before the page finished loading) 
- Amazon.com: +100 ms (speed decrease) -> -1% sales loss 
A thousandth of a second is not a long time, yet the impact is quite significant. Even if you’re not a large company (or just hope to become one), a loss is still a loss. However, there is a solution to this problem, take advantage.
Many of the other consequences of poor performance were discovered more than a decade ago:
- Lower perceived credibility (Fogg et al. 2001)
- Lower perceived quality (Bouch, Kuchinsky, and Bhatti 2000)
- Increased user frustration (Ceaparu et al. 2004)
- Increased blood pressure (Scheirer et al. 2002)
- Reduced flow rates (Novak, Hoffman, and Yung 200)
- Reduced conversion rates (Akamai 2007)
- Increased exit rates (Nielsen 2000)
- Are perceived as less interesting (Ramsay, Barbesi, and Preece 1998)
- Are perceived as less attractive (Skadberg and Kimmel 2004)
There are a number of resources that have been documenting the role of performance in success on the web, W3 Total Cache exists to give you a framework to tune your application or site without having to do years of research.
Why is W3 Total Cache better than other caching solutions?
It’s a complete framework. Most cache plugins available do a great job at achieving a couple of performance aims. Our plugin remedies numerous performance reducing aspects of any web site going far beyond merely reducing CPU usage (load) and bandwidth consumption for HTML pages alone. Equally important, the plugin requires no theme modifications, modifications to your .htaccess (mod_rewrite rules) or programming compromises to get started. Most importantly, it’s the only plugin designed to optimize all practical hosting environments small or large. The options are many and setup is easy.
I’ve never heard of any of this stuff; my site is fine, no one complains about the speed. Why should I install this?
Rarely do readers take the time to complain. They typically just stop browsing earlier than you’d prefer and may not return altogether. This is the only plugin specifically designed to make sure that all aspects of your site are as fast as possible. Google is placing more emphasis on the speed of a site as a factor in rankings; this plugin helps with that too.
It’s in every web site owner’s best interest is to make sure that the performance of your site is not hindering its success.
Which WordPress versions are supported?
To use all features in the suite, a minimum of version WordPress 2.8 with PHP 5.3 is required. Earlier versions will benefit from our Media Library Importer to get them back on the upgrade path and into a CDN of their choosing.
Why doesn’t minify work for me?
We’re always working to make this more simple and straight forward in future releases, but this is not an undertaking we can realize on our own. When you find a plugin, theme or file that is not compatible with minification reach out to the developer and ask them either to provide a minified version with their distribution or otherwise make sure their code is minification-friendly.
What about comments? Does the plugin slow down the rate at which comments appear?
On the contrary, as with any other action a user can perform on a site, faster performance will encourage more of it. The cache is so quickly rebuilt in memory that it’s no trouble to show visitors the most current version of a post that’s experiencing Digg, Slashdot, Drudge Report, Yahoo Buzz or Twitter effect.
Will the plugin interfere with other plugins or widgets?
No, on the contrary if you use the minify settings you will improve their performance by several times.
Does this plugin work with WordPress in network mode?
Indeed it does.
Does this plugin work with BuddyPress (bbPress)?
Will this plugin speed up WP Admin?
Yes, indirectly – if you have a lot of bloggers working with you, you will find that it feels like you have a server dedicated only to WP Admin once this plugin is enabled; the result, increased productivity.
Which web servers do you support?
We are aware of no incompatibilities with apache 1.3+, nginx 0.7+, IIS 5+ or litespeed 4.0.2+. If there’s a web server you feel we should be actively testing (e.g. lighttpd), we’re interested in hearing.
Is this plugin server cluster and load balancer friendly?
Yes, built from the ground up with scale and current hosting paradigms in mind.
What is the purpose of the “Media Library Import” tool and how do I use it?
The media library import tool is for old or “messy” WordPress installations that have attachments (images etc in posts or pages) scattered about the web server or “hot linked” to 3rd party sites instead of properly using the media library.
The tool will scan your posts and pages for the cases above and copy them to your media library, update your posts to use the link addresses and produce a .htaccess file containing the list of of permanent redirects, so search engines can find the files in their new location.
You should backup your database before performing this operation.
How do I find the JS and CSS to optimize (minify) them with this plugin?
Use the “Help” button available on the Minify settings tab. Once open, the tool will look for and populate the CSS and JS files used in each template of the site for the active theme. To then add a file to the minify settings, click the checkbox next to that file. The embed location of JS files can also be specified to improve page render performance. Minify settings for all installed themes can be managed from the tool as well by selecting the theme from the drop down menu. Once done configuring minify settings, click the apply and close button, then save settings in the Minify settings tab.
I don’t understand what a CDN has to do with caching, that’s completely different, no?
Technically no, a CDN is a high performance cache that stores static assets (your theme files, media library etc) in various locations throughout the world in order to provide low latency access to them by readers in those regions.
How do I use an Origin Pull (Mirror) CDN?
Login to your CDN providers control panel or account management area. Following any set up steps they provide, create a new “pull zone” or “bucket” for your site’s domain name. If there’s a set up wizard or any troubleshooting tips your provider offers, be sure to review them. In the CDN tab of the plugin, enter the hostname your CDN provider provided in the “replace site’s hostname with” field. You should always do a quick check by opening a test file from the CDN hostname, e.g. http://cdn.domain.com/favicon.ico. Troubleshoot with your CDN provider until this test is successful.
Now go to the General tab and click the checkbox and save the settings to enable CDN functionality and empty the cache for the changes to take effect.
How do I configure Amazon Simple Storage Service (Amazon S3) or Amazon CloudFront as my CDN?
First create an S3 account (unless using origin pull); it may take several hours for your account credentials to be functional. Next, you need to obtain your “Access key ID” and “Secret key” from the “Access Credentials” section of the “Security Credentials” page of “My Account.” Make sure the status is “active.” Next, make sure that “Amazon Simple Storage Service (Amazon S3)” is the selected “CDN type” on the “General Settings” tab, then save the changes. Now on the “Content Delivery Network Settings” tab enter your “Access key,” “Secret key” and enter a name (avoid special characters and spaces) for your bucket in the “Create a bucket” field by clicking the button of the same name. If using an existing bucket simply specify the bucket name in the “Bucket” field. Click the “Test S3 Upload” button and make sure that the test is successful, if not check your settings and try again. Save your settings.
Unless you wish to use CloudFront, you’re almost done, skip to the next paragraph if you’re using CloudFront. Go to the “General Settings” tab and click the “Enable” checkbox and save the settings to enable CDN functionality. Empty the cache for the changes to take effect. If preview mode is active you will need to “deploy” your changes for them to take effect.
To use CloudFront, perform all of the steps above, except select the “Amazon CloudFront” “CDN type” in the “Content Delivery Network” section of the “General Settings” tab. When creating a new bucket, the distribution ID will automatically be populated. Otherwise, proceed to the AWS Management Console and create a new distribution: select the S3 Bucket you created earlier as the “Origin,” enter a CNAME if you wish to add one or more to your DNS Zone. Make sure that “Distribution Status” is enabled and “State” is deployed. Now on “Content Delivery Network” tab of the plugin, copy the subdomain found in the AWS Management Console and enter the CNAME used for the distribution in the “CNAME” field.
You may optionally, specify up to 10 hostnames to use rather than the default hostname, doing so will improve the render performance of your site’s pages. Additional hostnames should also be specified in the settings for the distribution you’re using in the AWS Management Console.
Now go to the General tab and click the “Enable” checkbox and save the settings to enable CDN functionality and empty the cache for the changes to take effect. If preview mode is active you will need to “deploy” your changes for them to take effect.
How do I configure Rackspace Cloud Files as my CDN?
First create an account. Next, in the “Content Delivery Network” section of the “General Settings” tab, select Rackspace Cloud Files as the “CDN Type.” Now, in the “Configuration” section of the “Content Delivery Network” tab, enter the “Username” and “API key” associated with your account (found in the API Access section of the rackspace cloud control panel) in the respective fields. Next enter a name for the container to use (avoid special characters and spaces). If the operation is successful, the container’s ID will automatically appear in the “Replace site’s hostname with” field. You may optionally, specify the container name and container ID of an existing container if you wish. Click the “Test Cloud Files Upload” button and make sure that the test is successful, if not check your settings and try again. Save your settings. You’re now ready to export your media library, theme and any other files to the CDN.
You may optionally, specify up to 10 hostnames to use rather than the default hostname, doing so will improve the render performance of your site’s pages.
Now go to the General tab and click the “Enable” checkbox and save the settings to enable CDN functionality and empty the cache for the changes to take effect. If preview mode is active you will need to “deploy” your changes for them to take effect.
What is the purpose of the “modify attachment URLs” button?
If the domain name of your site has changed, this tool is useful in updating your posts and pages to use the current addresses. For example, if your site used to be www.domain.com, and you decided to change it to domain.com, the result would either be many “broken” images or many unnecessary redirects (which slow down the visitor’s browsing experience). You can use this tool to correct this and similar cases. Correcting the URLs of your images also allows the plugin to do a better job of determining which images are actually hosted with the CDN.
As always, it never hurts to back up your database first.
Is this plugin comptatible with TDO Mini Forms?
Captcha and recaptcha will work fine, however you will need to prevent any pages with forms from being cached. Add the page’s URI to the “Never cache the following pages” box on the Page Cache Settings tab.
Is this plugin comptatible with GD Star Rating?
Yes. Follow these steps:
- Enable dynamic loading of ratings by checking GD Star Rating -> Settings -> Features “Cache support option”
- If Database cache enabled in W3 Total Cache add
wp_gdsrto “Ignored query stems” field in the Database Cache settings tab, otherwise ratings will not updated after voting
- Empty all caches
I see garbage characters instead of the normal web site, what’s going on here?
If a theme or it’s files use the call
php_flush() or function
flush() that will interfere with the plugins normal operation; making the plugin send cached files before essential operations have finished. The
flush() call is no longer necessary and should be removed.
How do I cache only the home page?
/.+ to page cache “Never cache the following pages” option on the page cache settings tab.
I’m getting blank pages or 500 error codes when trying to upgrade on WordPress in network mode
First, make sure the plugin is not active (disabled) network-wide. Then make sure it’s deactivated network-wide. Now you should be able to successful upgrade without breaking your site.
A notification about file owner appears along with an FTP form, how can I resolve this?
The plugin uses WordPress FileSystem functionality to write to files. It checks if the file owner, file owner group of created files match process owner. If this is not the case it cannot write or modify files.
Typically, you should tell your web host about the permission issue and they should be able to resolve it.
You can however try adding define(‘FS_METHOD’, ‘direct’); to wp-config.php to circumvent the file and folder checks.
This is too good to be true, how can I test the results?
You will be able to see it instantly on each page load, but for tangible metrics, consider the following tools:
I don’t have time to deal with this, but I know I need it. Will you help me?
Yes! Please reach out to us and we’ll get you acclimated so you can “set it and forget it.”
Install the plugin to read the full FAQ on the plugins FAQ tab.
- Fixed fatal error during media file upload with CDN module active
- Fixed removal of empty values, JSON encoded string in attribute, trailing quote at end of tag, and the handling of anchors in HTML minify
- Fixed undefined index warning
- Fixed fatal error when purging CDN using full site delivery
- Fixed undefined variable notice
- Fixed “No such file or directory” warning
- Fixed writing to PHP error log rather than WordPress debug log
- Fixed default referrer policy should be “no-referrer-when-downgrade”
- Fixed php_flag error related to browser cache, using ini_set instead
- Fixed CloudFlare IPv6 check undefined offset
- Fixed Undefined constant WP_ROOT
- Fixed frame-ancestors being overwritten by frame-src
- Fixed missing semicolon in nginx configuration
- Fixed HTTP/2 URLs handling for browser cache and CDN modules
- Fixed display of CDN debug information
- Fixed CSS Minification with Google Fonts when included via “Include external files/libraries” and non-latin character-sets are loaded
- Fixed media query string not updating when all caches were purged
- Fixed double slash with ABSPATH if file exists
- Fixed setting max-age and expires header simultaneously
- Fixed SASL detection for PECL Memcached
- Fixed handling of manually entered objects to be purged on CDN
- Fixed query string handling in Nginx
- Improved error handling with Cloudfront
- Improved page cache logging
- Improved multi-tenant support for memory-based caching engines
- Improved CSS minification
- Improved purge behavior for changed media objects when using CDN
- Improved compatibility with sitemap plugins
- Added support for Memcached for Nginx
- Added support for caching webm files
- Added Brotli HTTP compression support
- Added StackPath full site delivery support
- Added wc_session to the list of ignored query stems for improved WooCommerce compatibility
- Fixed minified files not being hosted by CDN when enabled if “host minified files” is disabled
- Fixed warning thrown when purge all was selected (via nigrosimone)
- Fixed undefined offset error in fragment cache
- Fixed MaxCDN test button failure when debug mode is enabled
- Fixed purging of feeds when cache feeds option is enabeld
- Improved handling of errors when full site delivery isn’t set
- Improved nginx.conf to support xml caching
- Improved nginx.conf to support HSTS for static files
- Improved minify’s handling of query strings
- Improved database caching, frequent wp_options no longer flush posts or comments data
- Improved Limelight Networks CDN integration
- Improved FAQ, they’re now hosted in the GitHub public repository
- Improved handling for /<![CDATA[/ in HTML minify engine
- Imporved garbage collection for basic disk caching
- Improved HSTS support (via Dave Welsh)
- Improved reliabilty of CSS embed options
- Improved New Relic requirements in compatibility test
- Added StackPath CDN integration (including full site delivery)
- Added support for page cache priming via WP-CLI via prime function
- Added filter support for managing cache groups
- Added API for flushing individual cache groups via flush_group function
- Added purge support for JSON cache e.g. cached REST API requests
- Added filter support for managing database cache settings
- Added filter support before (w3tc_process_content) and after (w3tc_processed_content) a cache object is created
- Added compatibility for AMPforWP plugin
- Added JSON caching support for Pro subscribers
- Added additional security headers (via amiga-500)
- Fixed anonymous usage tracking, default to disabled
- Fixed incorrect minify cache data written if target directory missing
- Fixed empty minify cache file written when file locking enabled
- Fixed missing commas in CSS (via nigrosimone)
- Fixed typo in object cache engine (via Furniel)
- Fixed incorrect reuse of redis connections when persistent connections option enabled
- Fixed reliability of Google Drive (via jikamens)
- Fixed handling of UTF-8 encoded files by writing them in binary (via jikamens)
- Improved Full Site Delivery configuration user flow on the General and CDN settings screens
- Improved content type matching and cache hits as a result
- Improved minify file locking logic
- Improved visual langage of the compatibility test (via Furniel)
- Improved configuration file management
- Improved MaxCDN set up wizard
- Improved page cache’s accepted query string handling to handle optional values and add support for disk enhanced mode (via amiga-500, nigrosimone)
- Improved handling of timeouts to origin push CDN proviers
- Added HTTP/2 push headers for disk enhanced page caching (via nigrosimone)
- Added X-Forwarded-Proto header for use cases like HTTPS recognition behind proxies or load balancers
- Added multiple CDN support i.e. static file objects and pages, posts, feeds, API responses etc to use different respective CDN providers
- Added page caching by cookie name or value (sponsored by SQweb)
- Added toggle for CORS header to improve inter-operatbility with various CDN providers
- Added support for CDN hosted media to media library (inspired by amiga-500)
- Added object caching of AJAX calls (via andyexeter)
- Enterprise features are now available to Pro subscribers! Including reading from multiple databases concurrently and purging caches across multiple hosts via a Message Bus
- Fixed regression with browser caching and query strings
- Fixed handling of HTTP compressed documents in PHP v5.3 (via amiga-500)
- Fixed a bug with accelerated mobile pages (via nigrosimone)
- Improved reliability of minify in manual mode
- Improved file name generation on Windows for IIS servers
- Improved handling of # in URLs
- Improved handling of exclusions for e-commerce in Genesis Framework
- Improved handling of headers for Microsoft Azure
- Improved functionality with existing Cloudfront Distributions when configuring Full Site Delivery
- Improved minify debug logging
- Improved handling of URLs that omit the protocol
- Improved handling of custom files with CDN (via amiga-500)
- Updated CSSTidy library (via nigrosimone and amiga-500)
- Added Swarmify Video Optimization Extension [Hat tip the Swarmify Team]
- Added flushing of AMP pages
- Fixed security issue by protecting configuration data by adding .php to relevant files
- Fixed security issue with the creation of dot folders that could be abused
- Fixed handling HTTP compression for uncached pages
- Fixed handling of .svgz files
- Added expiration headers to webP images
- Added support for Microsoft Azure’s latest API
- Added ability to cache WP Admin. Recommended setting, is off. (Improved WP Admin performance with object caching enabled)
- Added HTTP/2 Push support for minified files
- Added option management support for wp-cli
- Improved handling of uncompressed minified files
- Improved handling of purging of modified pages / posts
- Improved compatibility with Rackspace Cloud Files
- Improved initial CDN configuration reliability
- Improved reliability of object caching
- Improved PHP 7.0 compatibility
- Improved PHP 4.3 compatibility
- Improved HTTP/2 support
- Improved CSS embed handling
- Improved reliability of object cache, transients now fallback to database
- Improved handling of cached http compressed objects
- Fixed missing namespace, which caused issues with other implementations of Google APIs
- Fixed handling Cloudflare zone list being incomplete for users with many zones
- Added extension to support Accelerated Mobile Pages (AMP)
- Added notification for users that are still using PHP 5.2 (end of life in 2011)
- Improved default settings
- Improved compatibility with Yoast SEO sitemap caching
- Improved compatability with Jetpack
- Improved directory handling on IIS
- Improved backwards compatibility for 3rd party implementations against legacy W3TC functions
- Fixed XSS vulnerability
- Fixed issues with dismissing overlays
- Fixed handling of tilde in URLs
- Fixed issue with HTTP compression header when using mfunc calls
- Fixed cache ID issue with minify in network mode
- Fixed rare issue of caching empty document when some PHP errors occur in themes or plugins
- Fixed caching of query strings
- Added support for APCu Opcode Cache
- Added support for Redis
- Added support for Google Drive
- Added support for Amazon S3-compatible stroage services
- Added support for PECL memcached
- Added support for srcset elements
- Added support for Rackspace CDN Origin Pull
- Added support for minification of external fonts
- Added support for WOFF2 font format
- Added support for FTPS (FTP-SSL, S-FTP)
- Added YUI Compressor’s PHP Port of the CSS minifier
- Added Narcissus’ JS minifier
- Added purge of parent page when attachments are added or updated
- Added Highwinds CDN provider
- Added “Validate Timestamps” option for compatible opcode caches functions like apc.stat are enabled
- Added Full Site Delivery for Pro subscribers
- Added HTTP Strict Transport Security (HSTS) support
- Added a sample extension for developers to reference
- Added Rackspace Cloud Files Multi-Region Support
- Added more support for exclusions to database cache
- Added more optionality to minifiers
- Added WPML Performance Extension
- Added use of namespace which creates mininum dependency on version PHP 5.3
- Improved PHP 5.6 compatibility
- Improved PHP 7 compatibility
- Improved performance menu in admin bar, including purging of specific cache engines and more
- Improved SSL interoperability
- Improved reliablity of test buttons
- Improved nomenclature of caching files for higher cache hit rates
- Improved nginx compatibility
- Improved WP CLI support
- Improved Cloudflare compatibility (now using latest APIs), Cloudflare must be re-authorized
- Improved AWS API compatibility (now using latest APIs)
- Improved Rackspace Cloud Files compatibility (now using latest APIs)
- Improved page cache purge for extensions like cloudflare and other reverse proxy use cases
- Improved extension framework functionality
- Improved compatibility of headers like ETag and content encoding
- Improved template fragment caching
- Improved notifications, warnings and errors
- Improved moble user agents detection
- Improved security with nonces and form elements
- Improved security throughout the codebase
- Improved detail of debug messages
- Improved Amazon SNS security (validation)
- Improved minify’s ability to match script tags without type attribute
- Fixed undefined w3tc_button_link
- Fixed support and other form submissions
- Fixed extension enabled key error
- Fixed Test CDN errors
- Fixed trailing slashes in custom wp content path and Minify
- Fixed WP_PLUGIN_DIR not being available when object-cache.php is loaded and W3TC constant not set
- Fixed Minify Auto and restructuring of JS code placement on page
- Fixed remove / replace drop in file on plugins page
- Fixed false positive check for legacy code
- Fixed deprecated wpdb escape
- Fixed Fragment Caching and APC anomalies
- Fixed cached configs causing 500 error on interrupted file writes
- Fixed readfile errors on servers with the functionality disabled
- Fixed false positives for license key verification
- Fixed debug information not printed on cached pages
- Fixed backwards compatibility and flushing and added doing it wrong notification
- Fixed “Prevent caching of objects after settings change”
- Fixed “Use late init” being shown as enabled with Disc:Enhanced
- Fixed missing param in APC cache method declaration
- Fixed user roles property not begin an array
- Fixed adding empty Vary header
- Fixed notice on failed upgrade licencing check
- Fixed Database Cache description text
- Fixed duplicate bb10 agents
- Fixed settings link in Minify Auto notification
- Fixed notice with undefined constant
- Fixed nginx configuration and Referrer, User Groups setting
- Fixed Genesis settings and Suhosin field name limit error
- Fixed Genesis and Fragment Caching (caching categories etc)
- Fixed CDN being enabled when creating NetDNA / MaxCDN pull zone
- Fixed NewRelic related notice in compatibility popup
- Fixed trailing slash issue in filename to url conversion
- Fixed issue with wp in subdirectory and relative minimal manual urls
- Fixed issue with widget styling
- Fixed issue with Purge All button action
- Fixed issue with exporting of settings
- Fixed issue with plugin interferring with preview theme
- Fixed issue with malformed config files
- Added caching of list of posts pages (tags, categories etc) to Genesis extension a long with flush it checkbox
- Added typecasting on expiration time in object cache drop-in
- Added capability check for save options
- Added FeedBurner extension
- Added woff support to Browser Cache
- Added new CloudFlare IPs
- Added support for WordPress defined charset and collate in CDN queue table creation
- Added WordPress SEO by Yoast extension
- Added *.less to CDN theme uploads and MIME
- Added default settings for MaxCDN Pull Zone creation
- Added call to change MaxCDN canonical header setting to match plugin setting
- Added one button default pull zone creation to MaxCDN without refresh
- Added MaxCDN authorization validation
- Added whitelist IPs notification for MaxCDN
- Added support for use of existing zones without refresh
- Added new mime types
- Added support for separate domains for frontend and admin backend
- Added CloudFlare as an extension
- Added nofollow to blogroll links
- Added DEV mode support to PRO version
- Added EDGE MODE functionality
- Improved wrapper functions in plugins.php for plugin / theme authors
- Improved reliability of NetDNA / MaxCDN API calls by using WP HTTP and not cURL
- Improved Fragment Caching debug information
- Improved preview mode, removed query string requirement
- Improved FAQ structure
- Improved empty minify/pgcache cache notification when using CDN
- Improved default settings for MaxCDN zone creation
- Improved CDN queue performance
- Improved blogmap url sanitation
- Improved MaxCDN automatic zone creation process
- Improved license key saving and Pro mode activation on Pro license purchases
- Updated EDGE MODE: Full site mirroring support for MaxCDN
- Updated translations
Plugin uses its own database tables: