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Caddyfile Directives

Directives are functional keywords that appear within site blocks. Sometimes, they may open blocks of their own which can contain subdirectives, but directives cannot be used within other directives unless noted. For example, you can't use basicauth inside a file_server block, because file_server does not know how to do authentication. However, you may use some directives within special directive blocks like handle and route because they are specifically designed to group HTTP handler directives.

The following directives come standard with Caddy, and can be used in the HTTP Caddyfile:

Directive Description
abort Aborts the HTTP request
acme_server An embedded ACME server
basicauth Enforces HTTP Basic Authentication
bind Customize the server's socket address
encode Encodes (usually compresses) responses
error Trigger an error
file_server Serve files from disk
forward_auth Delegate authentication to an external service
handle A mutually-exclusive group of directives
handle_errors Defines routes for handling errors
handle_path Like handle, but strips path prefix
header Sets or removes response headers
import Include snippets or files
invoke Invoke a named route
log Enables access/request logging
map Maps an input value to one or more outputs
method Change the HTTP method internally
metrics Configures the Prometheus metrics exposition endpoint
php_fastcgi Serve PHP sites over FastCGI
push Push content to the client using HTTP/2 server push
redir Issues an HTTP redirect to the client
request_body Manipulates request body
request_header Manipulates request headers
respond Writes a hard-coded response to the client
reverse_proxy A powerful and extensible reverse proxy
rewrite Rewrites the request internally
root Set the path to the site root
route A group of directives treated literally as single unit
skip_log Skip access logging for matched requests
templates Execute templates on the response
tls Customize TLS settings
tracing Integration with OpenTelemetry tracing
try_files Rewrite that depends on file existence
uri Manipulate the URI
vars Set arbitrary variables

Syntax

The syntax of each directive will look something like this:

directive [<matcher>] <args...> {
	subdirective [<args...>]
}

The <carets> indicate tokens to be substituted by actual values.

The[brackets] indicate optional parameters.

The ellipses ... indicates a continuation, i.e. one or more parameters or lines.

Subdirectives are typically optional unless documented otherwise, even though they don't appear in [brackets].

Matchers

Most—but not all—directives accept matcher tokens, which let you filter requests. Matcher tokens are usually optional. Directives support matchers if you see this in a directive's syntax:

[<matcher>]

Because matcher tokens all work the same, the various possibilities for the matcher token will not be described on every page, to reduce duplication. Instead, refer to the matcher documentation for a detailed explanation of the syntax.

Directive order

Many directives manipulate the HTTP handler chain. The order in which those directives are evaluated matters, so a default ordering is hard-coded into Caddy.

You can override/customize this ordering by using the order global option or the route directive.

tracing

map
vars
root
skip_log

header
copy_response_headers # only in reverse_proxy's handle_response block
request_body

redir

# incoming request manipulation
method
rewrite
uri
try_files

# middleware handlers; some wrap responses
basicauth
forward_auth
request_header
encode
push
templates

# special routing & dispatching directives
invoke
handle
handle_path
route

# handlers that typically respond to requests
abort
error
copy_response # only in reverse_proxy's handle_response block
respond
metrics
reverse_proxy
php_fastcgi
file_server
acme_server

Sorting algorithm

For ease of use, the Caddyfile adapter sorts directives according to the following rules:

  • Differently named directives are sorted by their position in the default order. The default order can be overridden with the order global option. Directives from plugins do not have an order, so the order global option or the route directive should be used to set one.

  • Same-named directives are sorted according to their matchers.

    • The highest priority is a directive with a single path matcher.

      Path matchers are sorted by specificity, from most specific to least specific.

      In general, this is performed by sorting by the length of the path matcher. There is one exception where if the path ends in a * and the paths of the two matchers are otherwise the same, the matcher with no * is considered more specific and sorted higher.

      For example:

      • /foobar is more specific than /foo
      • /foo is more specific than /foo*
      • /foo/* is more specific than /foo*
    • A directive with any other matcher is sorted next, in the order it appears in the Caddyfile.

      This includes path matchers with multiple values, and named matchers.

    • A directive with no matcher (i.e. matching all requests) is sorted last.

  • The vars directive has its ordering by matcher reversed, because it involves setting values which can overwrite eachother, so the most specific matcher should be evaluated last.

  • The contents of the route directive ignores all the above rules, and preserves the order the directives appear within.