caddy-website/src/docs/markdown/extending-caddy/namespaces.md

title
Module Namespaces

Module Namespaces

Caddy guest modules are loaded generically as interface{} types. In order for the host modules to be able to use them, the loaded guest modules are usually type-asserted to a known type first. This page describes the mapping from module namespaces to Go types for all the standard modules.

Documentation for non-standard module namespaces can be found with the documentation for the host module that defines them.

One way to read this table is, "If your module is in <namespace>, then it should compile as <type>."

Namespace	Expected Type	Description
	caddy.App	Caddy app
caddy.fs	fs.FS	Virtual file system ⚠️ Experimental
caddy.logging.encoders.filter	logging.LogFieldFilter	Log field filter
caddy.logging.writers	caddy.WriterOpener	Log writers
caddy.storage	caddy.StorageConverter	Storage backends
http.authentication.hashes	caddyauth.Comparer	Password hashers/comparers
http.authentication.providers	caddyauth.Authenticator	HTTP authentication providers
http.handlers	caddyhttp.MiddlewareHandler	HTTP handlers
http.matchers	caddyhttp.RequestMatcher	HTTP request matchers
http.reverse_proxy.circuit_breakers	reverseproxy.CircuitBreaker	Reverse proxy circuit breakers
http.reverse_proxy.selection_policies	reverseproxy.Selector	Load balancing selection policies
http.reverse_proxy.transport	http.RoundTripper	HTTP reverse proxy transports
http.reverse_proxy.upstreams	reverseproxy.UpstreamSource	Dynamic upstream source ⚠️ Experimental
tls.certificates	caddytls.CertificateLoader	TLS certificate source
tls.handshake_match	caddytls.ConnectionMatcher	TLS connection matcher
tls.issuance	certmagic.Issuer	TLS certificate issuer
tls.get_certificate	certmagic.CertificateManager	TLS certificate manager ⚠️ Experimental
tls.stek	caddytls.STEKProvider	TLS session ticket key source