Ultimate Apache .htaccess configuration with examples and links to reasons

# ##############################################################################
# # CROSS-ORIGIN RESOURCE SHARING (CORS) #
# ##############################################################################

# ------------------------------------------------------------------------------
# | Cross-domain AJAX requests |
# ------------------------------------------------------------------------------

# Allow cross-origin AJAX requests.
# http://code.google.com/p/html5security/wiki/CrossOriginRequestSecurity
# http://enable-cors.org/

# <IfModule mod_headers.c>
# Header set Access-Control-Allow-Origin "*"
# </IfModule>

# ------------------------------------------------------------------------------
# | CORS-enabled images |
# ------------------------------------------------------------------------------

# Send the CORS header for images when browsers request it.
# https://developer.mozilla.org/en-US/docs/HTML/CORS_Enabled_Image
# http://blog.chromium.org/2011/07/using-cross-domain-images-in-webgl-and.html
# http://hacks.mozilla.org/2011/11/using-cors-to-load-webgl-textures-from-cross-domain-images/

<IfModule mod_setenvif.c>
 <IfModule mod_headers.c>
 <FilesMatch ".(cur|gif|ico|jpe?g|png|svgz?|webp)$">
 SetEnvIf Origin ":" IS_CORS
 Header set Access-Control-Allow-Origin "*" env=IS_CORS
 </FilesMatch>
 </IfModule>
</IfModule>

# ------------------------------------------------------------------------------
# | Web fonts access |
# ------------------------------------------------------------------------------

# Allow access to web fonts from all domains.

<IfModule mod_headers.c>
 <FilesMatch ".(eot|otf|tt[cf]|woff)$">
 Header set Access-Control-Allow-Origin "*"
 </FilesMatch>
</IfModule>


# ##############################################################################
# # ERRORS #
# ##############################################################################

# ------------------------------------------------------------------------------
# | 404 error prevention for non-existing redirected folders |
# ------------------------------------------------------------------------------

# Prevent Apache from returning a 404 error as the result of a rewrite
# when the directory with the same name does not exist.
# http://httpd.apache.org/docs/current/content-negotiation.html#multiviews
# http://www.webmasterworld.com/apache/3808792.htm

Options -MultiViews

# ------------------------------------------------------------------------------
# | Custom error messages / pages |
# ------------------------------------------------------------------------------

# Customize what Apache returns to the client in case of an error.
# http://httpd.apache.org/docs/current/mod/core.html#errordocument

ErrorDocument 404 /404.html


# ##############################################################################
# # INTERNET EXPLORER #
# ##############################################################################

# ------------------------------------------------------------------------------
# | Better website experience |
# ------------------------------------------------------------------------------

# Force Internet Explorer to render pages in the highest available mode
# in the various cases when it may not.
# http://hsivonen.iki.fi/doctype/ie-mode.pdf

<IfModule mod_headers.c>
 Header set X-UA-Compatible "IE=edge"
 # mod_headers cannot match based on the content-type, however, this
 # header should be send only for HTML pages and not for the other resources
 <FilesMatch ".(appcache|atom|crx|css|cur|eot|f4[abpv]|flv|gif|htc|ico|jpe?g|js|json(ld)?|m4[av]|manifest|map|mp4|oex|og[agv]|opus|otf|pdf|png|rdf|rss|safariextz|svgz?|swf|tt[cf]|vcf|vtt|webapp|web[mp]|woff|xml|xpi)$">
 Header unset X-UA-Compatible
 </FilesMatch>
</IfModule>

# ------------------------------------------------------------------------------
# | Cookie setting from iframes |
# ------------------------------------------------------------------------------

# Allow cookies to be set from iframes in Internet Explorer.
# http://msdn.microsoft.com/en-us/library/ms537343.aspx
# http://www.w3.org/TR/2000/CR-P3P-20001215/

# <IfModule mod_headers.c>
# Header set P3P "policyref="/w3c/p3p.xml", CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT""
# </IfModule>


# ##############################################################################
# # MIME TYPES AND ENCODING #
# ##############################################################################

# ------------------------------------------------------------------------------
# | Proper MIME types for all files |
# ------------------------------------------------------------------------------

<IfModule mod_mime.c>

 # Audio
 AddType audio/mp4 m4a f4a f4b
 AddType audio/ogg oga ogg opus

 # Data interchange
 AddType application/json json map
 AddType application/ld+json jsonld

 # JavaScript
 # Normalize to standard type.
 # http://tools.ietf.org/html/rfc4329#section-7.2
 AddType application/javascript js

 # Video
 AddType video/mp4 f4v f4p m4v mp4
 AddType video/ogg ogv
 AddType video/webm webm
 AddType video/x-flv flv

 # Web fonts
 AddType application/font-woff woff
 AddType application/vnd.ms-fontobject eot

 # Browsers usually ignore the font MIME types and simply sniff the bytes
 # to figure out the font type.
 # http://mimesniff.spec.whatwg.org/#matching-a-font-type-pattern

 # Chrome however, shows a warning if any other MIME types are used for
 # the following fonts.

 AddType application/x-font-ttf ttc ttf
 AddType font/opentype otf

 # Make SVGZ fonts work on the iPad.
 # https://twitter.com/FontSquirrel/status/14855840545
 AddType image/svg+xml svgz
 AddEncoding gzip svgz

 # Other
 AddType application/octet-stream safariextz
 AddType application/x-chrome-extension crx
 AddType application/x-opera-extension oex
 AddType application/x-web-app-manifest+json webapp
 AddType application/x-xpinstall xpi
 AddType application/xml atom rdf rss xml
 AddType image/webp webp
 AddType image/x-icon cur
 AddType text/cache-manifest appcache manifest
 AddType text/vtt vtt
 AddType text/x-component htc
 AddType text/x-vcard vcf

</IfModule>

# ------------------------------------------------------------------------------
# | UTF-8 encoding |
# ------------------------------------------------------------------------------

# Use UTF-8 encoding for anything served as text/html or text/plain.
AddDefaultCharset utf-8

# Force UTF-8 for certain file formats.
<IfModule mod_mime.c>
 AddCharset utf-8 .atom .css .js .json .jsonld .rss .vtt .webapp .xml
</IfModule>


# ##############################################################################
# # URL REWRITES #
# ##############################################################################

# ------------------------------------------------------------------------------
# | Rewrite engine |
# ------------------------------------------------------------------------------

# Turn on the rewrite engine and enable the FollowSymLinks option (this is
# necessary in order for the following directives to work).

# If your web host doesn't allow the FollowSymlinks option, you may need to
# comment it out and use Options +SymLinksIfOwnerMatch, but be aware of the
# performance impact.
# http://httpd.apache.org/docs/current/misc/perf-tuning.html#symlinks

# Also, some cloud hosting services require RewriteBase to be set.
# http://www.rackspace.com/knowledge_center/frequently-asked-question/why-is-mod-rewrite-not-working-on-my-site

<IfModule mod_rewrite.c>
 Options +FollowSymlinks
 # Options +SymLinksIfOwnerMatch
 RewriteEngine On
 # RewriteBase /
</IfModule>

# ------------------------------------------------------------------------------
# | Suppressing / Forcing the www. at the beginning of URLs |
# ------------------------------------------------------------------------------

# The same content should never be available under two different URLs,
# especially not with and without www. at the beginning. This can cause
# SEO problems (duplicate content), and therefore, you should choose one
# of the alternatives and redirect the other one.

# By default Option 1 (no www.) is activated.
# http://no-www.org/faq.php?q=class_b

# If you would prefer to use Option 2, just comment out all the lines
# from Option 1 and uncomment the ones from Option 2.

# IMPORTANT: NEVER USE BOTH RULES AT THE SAME TIME!

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

# Option 1: rewrite www.example.com → example.com

<IfModule mod_rewrite.c>
 RewriteCond %{HTTPS} !=on
 RewriteCond %{HTTP_HOST} ^www.(.+)$ [NC]
 RewriteRule ^ http://%1%{REQUEST_URI} [R=301,L]
</IfModule>

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

# Option 2: rewrite example.com → www.example.com

# Be aware that the following might not be a good idea if you use "real"
# subdomains for certain parts of your website.

# <IfModule mod_rewrite.c>
# RewriteCond %{HTTPS} !=on
# RewriteCond %{HTTP_HOST} !^www. [NC]
# RewriteCond %{SERVER_ADDR} !=127.0.0.1
# RewriteCond %{SERVER_ADDR} !=::1
# RewriteRule ^ http://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
# </IfModule>


# ##############################################################################
# # SECURITY #
# ##############################################################################

# ------------------------------------------------------------------------------
# | Clickjacking |
# ------------------------------------------------------------------------------

# Protect website against clickjacking.

# The example below sends the X-Frame-Options response header with the value
# DENY, informing browsers not to display the web page content in any frame.

# This might not be the best setting for everyone. You should read about the
# other two possible values for X-Frame-Options: SAMEORIGIN & ALLOW-FROM.
# http://tools.ietf.org/html/rfc7034#section-2.1

# Keep in mind that while you could send the X-Frame-Options header for all
# of your site’s pages, this has the potential downside that it forbids even
# non-malicious framing of your content (e.g.: when users visit your site using
# a Google Image Search results page).

# Nonetheless, you should ensure that you send the X-Frame-Options header for
# all pages that allow a user to make a state changing operation (e.g: pages
# that contain one-click purchase links, checkout or bank-transfer confirmation
# pages, pages that make permanent configuration changes, etc.).

# Sending the X-Frame-Options header can also protect your website against
# more than just clickjacking attacks: https://cure53.de/xfo-clickjacking.pdf.

# http://tools.ietf.org/html/rfc7034
# http://blogs.msdn.com/b/ieinternals/archive/2010/03/30/combating-clickjacking-with-x-frame-options.aspx
# https://www.owasp.org/index.php/Clickjacking

# <IfModule mod_headers.c>
# Header set X-Frame-Options "DENY"
# <FilesMatch ".(appcache|atom|crx|css|cur|eot|f4[abpv]|flv|gif|htc|ico|jpe?g|js|json(ld)?|m4[av]|manifest|map|mp4|oex|og[agv]|opus|otf|pdf|png|rdf|rss|safariextz|svgz?|swf|tt[cf]|vcf|vtt|webapp|web[mp]|woff|xml|xpi)$">
# Header unset X-Frame-Options
# </FilesMatch>
# </IfModule>

# ------------------------------------------------------------------------------
# | Content Security Policy (CSP) |
# ------------------------------------------------------------------------------

# Mitigate the risk of cross-site scripting and other content-injection attacks.

# This can be done by setting a Content Security Policy which whitelists
# trusted sources of content for your website.

# The example header below allows ONLY scripts that are loaded from the current
# site's origin (no inline scripts, no CDN, etc). This almost certainly won't
# work as-is for your site!

# For more details on how to craft a reasonable policy for your site, read:
# http://html5rocks.com/en/tutorials/security/content-security-policy (or the
# specification: http://w3.org/TR/CSP). Also, to make things easier, you can
# use an online CSP header generator such as: http://cspisawesome.com/.

# <IfModule mod_headers.c>
# Header set Content-Security-Policy "script-src 'self'; object-src 'self'"
# <FilesMatch ".(appcache|atom|crx|css|cur|eot|f4[abpv]|flv|gif|htc|ico|jpe?g|js|json(ld)?|m4[av]|manifest|map|mp4|oex|og[agv]|opus|otf|pdf|png|rdf|rss|safariextz|svgz?|swf|tt[cf]|vcf|vtt|webapp|web[mp]|woff|xml|xpi)$">
# Header unset Content-Security-Policy
# </FilesMatch>
# </IfModule>

# ------------------------------------------------------------------------------
# | File access |
# ------------------------------------------------------------------------------

# Block access to directories without a default document.
# You should leave the following uncommented, as you shouldn't allow anyone to
# surf through every directory on your server (which may includes rather private
# places such as the CMS's directories).

<IfModule mod_autoindex.c>
 Options -Indexes
</IfModule>

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

# Block access to hidden files and directories.
# This includes directories used by version control systems such as Git and SVN.

<IfModule mod_rewrite.c>
 RewriteCond %{SCRIPT_FILENAME} -d [OR]
 RewriteCond %{SCRIPT_FILENAME} -f
 RewriteRule "(^|/)." - [F]
</IfModule>

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

# Block access to files that can expose sensitive information.

# By default, block access to backup and source files that may be left by some
# text editors and can pose a security risk when anyone has access to them.
# http://feross.org/cmsploit/

# IMPORTANT: Update the <FilesMatch> regular expression from below to include
# any files that might end up on your production server and can expose sensitive
# information about your website. These files may include: configuration files,
# files that contain metadata about the project (e.g.: project dependencies),
# build scripts, etc..

<FilesMatch "(^#.*#|.(bak|config|dist|fla|in[ci]|log|psd|sh|sql|sw[op])|~)$">

 # Apache < 2.3
 <IfModule !mod_authz_core.c>
 Order allow,deny
 Deny from all
 Satisfy All
 </IfModule>

 # Apache ≥ 2.3
 <IfModule mod_authz_core.c>
 Require all denied
 </IfModule>

</FilesMatch>

# ------------------------------------------------------------------------------
# | Reducing MIME-type security risks |
# ------------------------------------------------------------------------------

# Prevent some browsers from MIME-sniffing the response.

# This reduces exposure to drive-by download attacks and should be enable
# especially if the web server is serving user uploaded content, content
# that could potentially be treated by the browser as executable.

# http://blogs.msdn.com/b/ie/archive/2008/07/02/ie8-security-part-v-comprehensive-protection.aspx
# http://msdn.microsoft.com/en-us/library/ie/gg622941.aspx
# http://mimesniff.spec.whatwg.org/

# <IfModule mod_headers.c>
# Header set X-Content-Type-Options "nosniff"
# </IfModule>

# ------------------------------------------------------------------------------
# | Reflected Cross-Site Scripting (XSS) attacks |
# ------------------------------------------------------------------------------

# (1) Try to re-enable the Cross-Site Scripting (XSS) filter built into the
# most recent web browsers.
#
# The filter is usually enabled by default, but in some cases it may be
# disabled by the user. However, in Internet Explorer for example, it can
# be re-enabled just by sending the X-XSS-Protection header with the
# value of 1.
#
# (2) Prevent web browsers from rendering the web page if a potential reflected
# (a.k.a non-persistent) XSS attack is detected by the filter.
#
# By default, if the filter is enabled and browsers detect a reflected
# XSS attack, they will attempt to block the attack by making the smallest
# possible modifications to the returned web page.
#
# Unfortunately, in some browsers (e.g.: Internet Explorer), this default
# behavior may allow the XSS filter to be exploited, thereby, it's better
# to tell browsers to prevent the rendering of the page altogether, instead
# of attempting to modify it.
#
# http://hackademix.net/2009/11/21/ies-xss-filter-creates-xss-vulnerabilities
#
# IMPORTANT: Do not rely on the XSS filter to prevent XSS attacks! Ensure that
# you are taking all possible measures to prevent XSS attacks, the most obvious
# being: validating and sanitizing your site's inputs.
#
# http://blogs.msdn.com/b/ie/archive/2008/07/02/ie8-security-part-iv-the-xss-filter.aspx
# http://blogs.msdn.com/b/ieinternals/archive/2011/01/31/controlling-the-internet-explorer-xss-filter-with-the-x-xss-protection-http-header.aspx
# https://www.owasp.org/index.php/Cross-site_Scripting_%28XSS%29

# <IfModule mod_headers.c>
# # (1) (2)
# Header set X-XSS-Protection "1; mode=block"
# <FilesMatch ".(appcache|atom|crx|css|cur|eot|f4[abpv]|flv|gif|htc|ico|jpe?g|js|json(ld)?|m4[av]|manifest|map|mp4|oex|og[agv]|opus|otf|pdf|png|rdf|rss|safariextz|svgz?|swf|tt[cf]|vcf|vtt|webapp|web[mp]|woff|xml|xpi)$">
# Header unset X-XSS-Protection
# </FilesMatch>
# </IfModule>

# ------------------------------------------------------------------------------
# | Secure Sockets Layer (SSL) |
# ------------------------------------------------------------------------------

# Rewrite secure requests properly in order to prevent SSL certificate warnings.
# E.g.: prevent https://www.example.com when your certificate only allows
# https://secure.example.com.

# <IfModule mod_rewrite.c>
# RewriteCond %{SERVER_PORT} !^443
# RewriteRule ^ https://example-domain-please-change-me.com%{REQUEST_URI} [R=301,L]
# </IfModule>

# ------------------------------------------------------------------------------
# | HTTP Strict Transport Security (HSTS) |
# ------------------------------------------------------------------------------

# Force client-side SSL redirection.

# If a user types example.com in his browser, the above rule will redirect
# him to the secure version of the site. That still leaves a window of
# opportunity (the initial HTTP connection) for an attacker to downgrade or
# redirect the request.

# The following header ensures that browser will ONLY connect to your server
# via HTTPS, regardless of what the users type in the address bar.

# http://tools.ietf.org/html/draft-ietf-websec-strict-transport-sec-14#section-6.1
# http://www.html5rocks.com/en/tutorials/security/transport-layer-security/

# IMPORTANT: Remove the includeSubDomains optional directive if the subdomains
# are not using HTTPS.

# <IfModule mod_headers.c>
# Header set Strict-Transport-Security "max-age=16070400; includeSubDomains"
# </IfModule>

# ------------------------------------------------------------------------------
# | Server software information |
# ------------------------------------------------------------------------------

# Avoid displaying the exact Apache version number, the description of the
# generic OS-type and the information about Apache's compiled-in modules.

# ADD THIS DIRECTIVE IN THE httpd.conf AS IT WILL NOT WORK IN THE .htaccess!

# ServerTokens Prod


# ##############################################################################
# # WEB PERFORMANCE #
# ##############################################################################

# ------------------------------------------------------------------------------
# | Compression |
# ------------------------------------------------------------------------------

<IfModule mod_deflate.c>

 # Force compression for mangled headers.
 # http://developer.yahoo.com/blogs/ydn/posts/2010/12/pushing-beyond-gzipping
 <IfModule mod_setenvif.c>
 <IfModule mod_headers.c>
 SetEnvIfNoCase ^(Accept-EncodXng|X-cept-Encoding|X{15}|~{15}|-{15})$ ^((gzip|deflate)s*,?s*)+|[X~-]{4,13}$ HAVE_Accept-Encoding
 RequestHeader append Accept-Encoding "gzip,deflate" env=HAVE_Accept-Encoding
 </IfModule>
 </IfModule>

 # Compress all output labeled with one of the following MIME-types
 # (for Apache versions below 2.3.7, you don't need to enable mod_filter
 # and can remove the <IfModule mod_filter.c> and </IfModule> lines
 # as AddOutputFilterByType is still in the core directives).
 <IfModule mod_filter.c>
 AddOutputFilterByType DEFLATE application/atom+xml 
 application/javascript 
 application/json 
 application/ld+json 
 application/rss+xml 
 application/vnd.ms-fontobject 
 application/x-font-ttf 
 application/x-web-app-manifest+json 
 application/xhtml+xml 
 application/xml 
 font/opentype 
 image/svg+xml 
 image/x-icon 
 text/css 
 text/html 
 text/plain 
 text/x-component 
 text/xml
 </IfModule>

</IfModule>

# ------------------------------------------------------------------------------
# | Content transformations |
# ------------------------------------------------------------------------------

# Prevent mobile network providers from modifying the website's content.
# http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9.5.

# <IfModule mod_headers.c>
# Header set Cache-Control "no-transform"
# </IfModule>

# ------------------------------------------------------------------------------
# | ETags |
# ------------------------------------------------------------------------------

# Remove ETags as resources are sent with far-future expires headers.
# http://developer.yahoo.com/performance/rules.html#etags.

# FileETag None doesn't work in all cases.
<IfModule mod_headers.c>
 Header unset ETag
</IfModule>

FileETag None

# ------------------------------------------------------------------------------
# | Expires headers |
# ------------------------------------------------------------------------------

# The following expires headers are set pretty far in the future. If you
# don't control versioning with filename-based cache busting, consider
# lowering the cache time for resources such as style sheets and JavaScript
# files to something like one week.

<IfModule mod_expires.c>

 ExpiresActive on
 ExpiresDefault "access plus 1 month"

 # CSS
 ExpiresByType text/css "access plus 1 year"

 # Data interchange
 ExpiresByType application/json "access plus 0 seconds"
 ExpiresByType application/ld+json "access plus 0 seconds"
 ExpiresByType application/xml "access plus 0 seconds"
 ExpiresByType text/xml "access plus 0 seconds"

 # Favicon (cannot be renamed!) and cursor images
 ExpiresByType image/x-icon "access plus 1 week"

 # HTML components (HTCs)
 ExpiresByType text/x-component "access plus 1 month"

 # HTML
 ExpiresByType text/html "access plus 0 seconds"

 # JavaScript
 ExpiresByType application/javascript "access plus 1 year"

 # Manifest files
 ExpiresByType application/x-web-app-manifest+json "access plus 0 seconds"
 ExpiresByType text/cache-manifest "access plus 0 seconds"

 # Media
 ExpiresByType audio/ogg "access plus 1 month"
 ExpiresByType image/gif "access plus 1 month"
 ExpiresByType image/jpeg "access plus 1 month"
 ExpiresByType image/png "access plus 1 month"
 ExpiresByType video/mp4 "access plus 1 month"
 ExpiresByType video/ogg "access plus 1 month"
 ExpiresByType video/webm "access plus 1 month"

 # Web feeds
 ExpiresByType application/atom+xml "access plus 1 hour"
 ExpiresByType application/rss+xml "access plus 1 hour"

 # Web fonts
 ExpiresByType application/font-woff "access plus 1 month"
 ExpiresByType application/vnd.ms-fontobject "access plus 1 month"
 ExpiresByType application/x-font-ttf "access plus 1 month"
 ExpiresByType font/opentype "access plus 1 month"
 ExpiresByType image/svg+xml "access plus 1 month"

</IfModule>

# ------------------------------------------------------------------------------
# | Filename-based cache busting |
# ------------------------------------------------------------------------------

# If you're not using a build process to manage your filename version revving,
# you might want to consider enabling the following directives to route all
# requests such as /css/style.12345.css to /css/style.css.

# To understand why this is important and a better idea than *.css?v231, read:
# http://stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring

# <IfModule mod_rewrite.c>
# RewriteCond %{REQUEST_FILENAME} !-f
# RewriteRule ^(.+).(d+).(js|css|png|jpe?g|gif)$ $1.$3 [L]
# </IfModule>

# ------------------------------------------------------------------------------
# | File concatenation |
# ------------------------------------------------------------------------------

# Allow concatenation from within specific style sheets and JavaScript files.

# e.g.:
#
# If you have the following content in a file
#
# <!--#include file="libs/jquery.js" -->
# <!--#include file="plugins/jquery.timer.js" -->
#
# Apache will replace it with the content from the specified files.

# <IfModule mod_include.c>
# <FilesMatch ".combined.js$">
# Options +Includes
# AddOutputFilterByType INCLUDES application/javascript application/json
# SetOutputFilter INCLUDES
# </FilesMatch>
# <FilesMatch ".combined.css$">
# Options +Includes
# AddOutputFilterByType INCLUDES text/css
# SetOutputFilter INCLUDES
# </FilesMatch>
# </IfModule>


# Redirects domain.com/file.html to domain.com/file
RewriteCond %{REQUEST_FILENAME} !-d # is not directory
RewriteCond %{REQUEST_FILENAME}.html -f # is an existing html file
RewriteCond %{REQUEST_URI} ^(.+).html$ # request URI ends with .html
RewriteRule (.*).html$ /$1 [R=301,L] # redirect from index.html to index