%s:%d: Caddyfile input is not formatted; Tip: use '--overwri

Error message

%s:%d: Caddyfile input is not formatted; Tip: use '--overwrite' to update your Caddyfile in-place instead of previewing it. Consult '--help' for more options

What it means

Error "%s:%d: Caddyfile input is not formatted; Tip: use '--overwrite' to update your Caddyfile in-place instead of previewing it. Consult '--help' for more options" thrown in caddyserver/caddy.

Source

Thrown at cmd/commandfuncs.go:741

		diff := difflib.Diff(
			strings.Split(string(input), "\n"),
			strings.Split(string(output), "\n"))
		for _, d := range diff {
			switch d.Delta {
			case difflib.Common:
				fmt.Printf("  %s\n", d.Payload)
			case difflib.LeftOnly:
				fmt.Printf("- %s\n", d.Payload)
			case difflib.RightOnly:
				fmt.Printf("+ %s\n", d.Payload)
			}
		}
	} else {
		fmt.Print(string(output))
	}

	if warning, diff := caddyfile.FormattingDifference(configFile, input); diff {
		return caddy.ExitCodeFailedStartup, fmt.Errorf(`%s:%d: Caddyfile input is not formatted; Tip: use '--overwrite' to update your Caddyfile in-place instead of previewing it. Consult '--help' for more options`,
			warning.File,
			warning.Line,
		)
	}

	return caddy.ExitCodeSuccess, nil
}

// handleEnvFileFlag loads the environment variables from the given --envfile
// flag if specified. This should be called as early in the command function.
func handleEnvFileFlag(fl Flags) error {
	var err error
	var envfileFlag []string
	envfileFlag, err = fl.GetStringSlice("envfile")
	if err != nil {
		return fmt.Errorf("reading envfile flag: %v", err)
	}

View on GitHub (pinned to 50e54ee279)

Solutions

Run 'caddy fmt --overwrite' to format the file in place, or apply the shown formatting changes manually.

When it happens

Trigger: Thrown at cmd/commandfuncs.go:741 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of caddyserver/caddy@50e54ee279 (2026-08-15). Data as JSON: /api/errors/c7d0e66104ac91a5. Report an issue: GitHub.