gohugoio/hugo · error

no Dart Sass binary found in $PATH

Error message

no Dart Sass binary found in $PATH

What it means

Returned by the Dart Sass client constructor when hugo.DartSassBinaryName is empty, meaning Hugo probed $PATH and found no dart-sass-embedded / sass binary. Without the binary, Dart Sass transpilation cannot run, so ToCSS with transpiler='dartsass' fails (or falls back depending on cache config).

Solutions

1. Install Dart Sass embedded and ensure it is on $PATH: see https://gohugo.io/functions/css/sass/#dart-sass for the official install steps (e.g. download dart-sass-embedded release or `npm install -g sass`).
2. Verify with `sass --version` from the same shell/environment Hugo runs in.
3. Alternatively set transpiler='libsass' (requires Hugo extended) if you cannot install Dart Sass.

Example fix

// before: no binary
$ hugo
ERROR: no Dart Sass binary found in $PATH

// after
$ npm install -g sass
$ hugo

// Probe PATH for the Dart Sass binary before building.
import "os/exec"

func dartSassAvailable() bool {
    _, err := exec.LookPath("sass") // or dart-sass-embedded
    return err == nil
}

When it happens

Trigger: Calling css.Sass / css.ToCSS with options transpiler='dartsass' (the default for .scss) on a machine where the Dart Sass embedded binary is not installed or not on $PATH. New() checks hugo.DartSassBinaryName and returns this error.

Common situations: Fresh CI/CD runner without Dart Sass installed, local dev after uninstalling sass, a Docker image that lacks the binary, or PATH not propagating the install into Hugo's process environment.

Related errors

• unsupported Dart Sass version detected, please upgrade to…
• could not find in the import context
• got unexpected EOF when executing
• pandoc not found in $PATH, cannot render
• failed to execute 'go

AI-assisted analysis of gohugoio/hugo@52c9bd7908 (2026-08-09). Data as JSON: /api/errors/7554729b6fd31bee. Report an issue: GitHub.

Appendix: source

Thrown at resources/resource_transformers/tocss/dartsass/client.go:52

	"github.com/spf13/afero"

	"github.com/mitchellh/mapstructure"
)

// used as part of the cache key.
const transformationName = "tocss-dart"

// See https://github.com/sass/dart-sass-embedded/issues/24
// Note: This prefix must be all lower case.
const dartSassStdinPrefix = "hugostdin:"

func New(fs *filesystems.SourceFilesystem, rs *resources.Spec) (*Client, error) {
	if !Supports() {
		return &Client{}, nil
	}

	if hugo.DartSassBinaryName == "" {
		return nil, fmt.Errorf("no Dart Sass binary found in $PATH")
	}

	if !hugo.IsDartSassGeV2() {
		return nil, fmt.Errorf("unsupported Dart Sass version detected, please upgrade to Dart Sass 1.63.0 or later, see https://gohugo.io/functions/css/sass/#dart-sass")
	}

	if err := rs.ExecHelper.Sec().CheckAllowedExec(hugo.DartSassBinaryName); err != nil {
		return nil, err
	}

	var (
		transpiler *godartsass.Transpiler
		err        error
		infol      = rs.Logger.InfoCommand("Dart Sass")
		warnl      = rs.Logger.WarnCommand("Dart Sass")
	)

	transpiler, err = godartsass.Start(godartsass.Options{

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