gohugoio/hugo · error

postcss config not found

Error message

postcss config %q not found

What it means

Thrown by the PostCSS transformer when options.Config is explicitly set by the user but the named config file cannot be resolved by BaseFs.ResolveJSConfigFile. Auto-discovered configs (postcss.config.js/mjs/cjs) never trigger this; it fires only for a missing user-specified config path.

Solutions

1. Confirm the file at the path given by options["config"] exists; the error echoes the exact unresolved path.
2. Use an absolute path or place postcss.config.js at the project root and remove the 'config' option to rely on auto-discovery.
3. If you use Tailwind, ensure the postcss config actually loads @tailwindcss/postcss or tailwindcss plugin as intended.

Example fix

// before
{{ $css := resources.Get "css/main.css" | css.PostCSS (dict "config" "postcss/prod.config.js") }}

// after
{{ $css := resources.Get "css/main.css" | css.PostCSS }} // uses ./postcss.config.js

if cfg, ok := opts["config"]; ok {
    p := filepath.Clean(fmt.Sprint(cfg))
    if _, err := os.Stat(p); err != nil {
        return fmt.Errorf("postcss config %q not found", p)
    }
}

When it happens

Trigger: Calling css.PostCSS with options map containing "config": "./postcss/prod.js" where that path is not resolvable relative to the project working dir / JS config filesystem.

Common situations: Moving/deleting a custom postcss config without updating the template option; using a path that exists only in a different module or theme; case mismatch on case-sensitive filesystems.

Related errors

• babel config not found
• : failed to transform ( )
• cannot use --renderToMemory with --destination
• cardinalityThreshold threshold must be between 0 and 100
• could not find in the import context

AI-assisted analysis of gohugoio/hugo@52c9bd7908 (2026-08-09). Data as JSON: /api/errors/b1047bb5c8f5cebf. Report an issue: GitHub.

Appendix: source

Thrown at resources/resource_transformers/cssjs/postcss.go:179

	if options.Config != "" {
		configFile = options.Config
	} else {
		for _, name := range []string{"postcss.config.js", "postcss.config.mjs", "postcss.config.cjs"} {
			configFile = t.rs.BaseFs.ResolveJSConfigFile(name)
			if configFile != "" {
				break
			}
		}
	}

	if configFile != "" {
		configFile = filepath.Clean(configFile)
		// We need an absolute filename to the config file.
		if !filepath.IsAbs(configFile) {
			configFile = t.rs.BaseFs.ResolveJSConfigFile(configFile)
			if configFile == "" && options.Config != "" {
				// Only fail if the user specified config file is not found.
				return fmt.Errorf("postcss config %q not found", options.Config)
			}
		}
	}

	var cmdArgs []any

	if configFile != "" {
		infol.Logf("use config file %q", configFile)
		cmdArgs = []any{"--config", configFile}
	}

	if optArgs := options.toArgs(); len(optArgs) > 0 {
		cmdArgs = append(cmdArgs, collections.StringSliceToInterfaceSlice(optArgs)...)
	}

	var errBuf bytes.Buffer

	stderr := io.MultiWriter(infow, &errBuf)

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