An opinionated directive that proxies requests to a PHP FastCGI server such as php-fpm.

Caddy's reverse_proxy is capable of serving any FastCGI application, but this directive is tailored specifically for PHP apps. This directive is actually just a convenient way to use a longer, more common configuration (below).

It expects that any index.php at the site root acts as a router. If that is not desirable, either perform your own URI rewrite or use something like the expanded form below and customize it to your needs.

It supports all the subdirectives of reverse_proxy and passes them through to the underlying reverse_proxy handler, plus a few subdirectives that customize the FastCGI transport specifically.

Most modern PHP apps work fine without extra subdirectives or customization. Subdirectives are usually only used in certain edge cases or with legacy PHP apps.


php_fastcgi [<matcher>] <php-fpm_gateways...> {
	split <substrings...>
	env [<key> <value>]
	root <path>
	index <filename>

	<any other reverse_proxy subdirectives...>
  • <php-fpm_gateways...> are the addresses of the FastCGI servers.
  • split sets the substrings for splitting the URI into two parts. The first matching substring will be used to split the "path info" from the path. The first piece is suffixed with the matching substring and will be assumed as the actual resource (CGI script) name. The second piece will be set to PATH_INFO for the CGI script to use. Default: .php
  • env sets an extra environment variable to the given value.
  • root sets the root folder to the site. Default: root directive.
  • index specifies the filename to treat as the directory index file. This affects the file matcher in the expanded form. Default: index.php

Since this directive is an opinionated wrapper over a reverse proxy, you can use any of reverse_proxy's subdirectives to customize it.

Expanded form

The php_fastcgi directive is the same as the following configuration:

route {
	# Add trailing slash for directory requests
	@canonicalPath {
		file {
			try_files {path}/index.php
		not path */
	redir @canonicalPath {path}/ 308

	# If the requested file does not exist, try index files
	@indexFiles {
		file {
			try_files {path} {path}/index.php index.php
			split_path .php
	rewrite @indexFiles {http.matchers.file.relative}

	# Proxy PHP files to the FastCGI responder
	@phpFiles {
		path *.php
	reverse_proxy @phpFiles <php-fpm_gateway> {
		transport fastcgi {
			split .php

Most modern PHP apps work well with this preset. If yours does not, feel free to borrow from this and customize it as needed instead of using the php_fastcgi shortcut.


Proxy all PHP requests to a FastCGI responder listening at


Same, but only for requests under /blog/:

php_fastcgi /blog/*

When using php-fpm listening via a unix socket:

php_fastcgi unix//run/php/php7.4-fpm.sock

The root directive is often used to specify the directory containing the PHP scripts:

root * /var/www/html