diff --git a/caddyconfig/httpcaddyfile/httptype.go b/caddyconfig/httpcaddyfile/httptype.go
index 9cf386a47f9..7159454b031 100644
--- a/caddyconfig/httpcaddyfile/httptype.go
+++ b/caddyconfig/httpcaddyfile/httptype.go
@@ -223,7 +223,7 @@ func (st ServerType) Setup(inputServerBlocks []caddyfile.ServerBlock,
 			hasDefaultLog = true
 		}
 		if _, ok := options["debug"]; ok && ncl.log.Level == "" {
-			ncl.log.Level = "DEBUG"
+			ncl.log.Level = zap.DebugLevel.CapitalString()
 		}
 		customLogs = append(customLogs, ncl)
 	}
@@ -241,7 +241,7 @@ func (st ServerType) Setup(inputServerBlocks []caddyfile.ServerBlock,
 		if _, ok := options["debug"]; ok {
 			customLogs = append(customLogs, namedCustomLog{
 				name: "default",
-				log:  &caddy.CustomLog{Level: "DEBUG"},
+				log:  &caddy.CustomLog{Level: zap.DebugLevel.CapitalString()},
 			})
 		}
 	}
diff --git a/modules/caddyhttp/fileserver/command.go b/modules/caddyhttp/fileserver/command.go
index 902c5f8ce6f..6a775097a7b 100644
--- a/modules/caddyhttp/fileserver/command.go
+++ b/modules/caddyhttp/fileserver/command.go
@@ -27,6 +27,7 @@ import (
 	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
 	caddytpl "github.com/caddyserver/caddy/v2/modules/caddyhttp/templates"
 	"github.com/caddyserver/certmagic"
+	"go.uber.org/zap"
 )
 
 func init() {
@@ -70,6 +71,7 @@ func cmdFileServer(fs caddycmd.Flags) (int, error) {
 	browse := fs.Bool("browse")
 	templates := fs.Bool("templates")
 	accessLog := fs.Bool("access-log")
+	debug := fs.Bool("debug")
 
 	var handlers []json.RawMessage
 
@@ -130,6 +132,14 @@ func cmdFileServer(fs caddycmd.Flags) (int, error) {
 		},
 	}
 
+	if debug {
+		cfg.Logging = &caddy.Logging{
+			Logs: map[string]*caddy.CustomLog{
+				"default": {Level: zap.DebugLevel.CapitalString()},
+			},
+		}
+	}
+
 	err := caddy.Run(cfg)
 	if err != nil {
 		return caddy.ExitCodeFailedStartup, err
diff --git a/modules/caddyhttp/reverseproxy/command.go b/modules/caddyhttp/reverseproxy/command.go
index ff19919f04d..481f6e00d49 100644
--- a/modules/caddyhttp/reverseproxy/command.go
+++ b/modules/caddyhttp/reverseproxy/command.go
@@ -28,6 +28,7 @@ import (
 	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
 	"github.com/caddyserver/caddy/v2/modules/caddyhttp/headers"
 	"github.com/caddyserver/caddy/v2/modules/caddytls"
+	"go.uber.org/zap"
 )
 
 func init() {
@@ -62,6 +63,7 @@ default, all incoming headers are passed through unmodified.)
 			fs.Bool("change-host-header", false, "Set upstream Host header to address of upstream")
 			fs.Bool("insecure", false, "Disable TLS verification (WARNING: DISABLES SECURITY BY NOT VERIFYING SSL CERTIFICATES!)")
 			fs.Bool("internal-certs", false, "Use internal CA for issuing certs")
+			fs.Bool("debug", false, "Enable verbose debug logs")
 			return fs
 		}(),
 	})
@@ -74,6 +76,7 @@ func cmdReverseProxy(fs caddycmd.Flags) (int, error) {
 	changeHost := fs.Bool("change-host-header")
 	insecure := fs.Bool("insecure")
 	internalCerts := fs.Bool("internal-certs")
+	debug := fs.Bool("debug")
 
 	httpPort := strconv.Itoa(caddyhttp.DefaultHTTPPort)
 	httpsPort := strconv.Itoa(caddyhttp.DefaultHTTPSPort)
@@ -198,6 +201,14 @@ func cmdReverseProxy(fs caddycmd.Flags) (int, error) {
 		AppsRaw: appsRaw,
 	}
 
+	if debug {
+		cfg.Logging = &caddy.Logging{
+			Logs: map[string]*caddy.CustomLog{
+				"default": {Level: zap.DebugLevel.CapitalString()},
+			},
+		}
+	}
+
 	err = caddy.Run(cfg)
 	if err != nil {
 		return caddy.ExitCodeFailedStartup, err
diff --git a/modules/caddyhttp/staticresp.go b/modules/caddyhttp/staticresp.go
index ccc70e2da5c..411a7bcc567 100644
--- a/modules/caddyhttp/staticresp.go
+++ b/modules/caddyhttp/staticresp.go
@@ -31,6 +31,7 @@ import (
 	"github.com/caddyserver/caddy/v2/caddyconfig"
 	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
 	caddycmd "github.com/caddyserver/caddy/v2/cmd"
+	"go.uber.org/zap"
 )
 
 func init() {
@@ -403,7 +404,7 @@ func cmdRespond(fl caddycmd.Flags) (int, error) {
 	if debug {
 		cfg.Logging = &caddy.Logging{
 			Logs: map[string]*caddy.CustomLog{
-				"default": {Level: "DEBUG"},
+				"default": {Level: zap.DebugLevel.CapitalString()},
 			},
 		}
 	}