gohugoio/hugo · error

failed to resolve output formats

Error message

failed to resolve output formats %v: %w

What it means

Thrown by PageConfigLate.Compile when the 'outputs' front matter list is non-empty but outputFormats.GetByNames cannot resolve one or more of the named output formats. The wrapped error is from the outputFormats lookup; the printed list is the value of p.Outputs.

Solutions

1. Use only output format names that are defined in your [outputFormats] config or built-in (html, amp, rss, json, etc.).
2. Define the missing custom output format under [outputFormats] and add it to the kind's outputs list.
3. Remove the 'outputs' front matter key to use the site default outputs for that page kind.

Example fix

# before
---
outputs: [htm]
---
# after
---
outputs: [html]
---

valid := map[string]bool{}
for _, f := range configuredOutputFormats { valid[f.Name] = true }
for _, name := range pcfg.Outputs {
    if !valid[name] { return fmt.Errorf("unknown output format %q", name) }
}

if err := pcfg.Compile(early, logger, formats); err != nil {
    return fmt.Errorf("outputs for %s: %w", path, err)
}

When it happens

Trigger: Front matter sets 'outputs: [foo]' (or a content adapter sets Outputs) where 'foo' is not one of the configured output format names (e.g. html, amp, rss, json, csv).

Common situations: Typo in an output format name, referencing a custom output format that was never defined under [outputFormats], or assuming a format exists in a theme without inheriting its config.

Related errors

• failed to decode page map
• failed to decode sites from front matter
• failed to resolve media type for
• media type not found
• cannot use --renderToMemory with --destination

AI-assisted analysis of gohugoio/hugo@52c9bd7908 (2026-08-09). Data as JSON: /api/errors/0ec8673973faced3. Report an issue: GitHub.

Appendix: source

Thrown at resources/page/pagemeta/page_frontmatter.go:457

// Compile sets up the page configuration after all fields have been set.
func (p *PageConfigLate) Compile(e *PageConfigEarly, logger loggers.Logger, outputFormats output.Formats) error {
	if e.IsFromContentAdapter {
		if err := mapstructure.WeakDecode(p.ContentAdapterData, p); err != nil {
			err = fmt.Errorf("failed to decode page map: %w", err)
			return err
		}
	}

	if p.Params == nil {
		p.Params = make(hmaps.Params)
	} else {
		hmaps.PrepareParams(p.Params)
	}

	if len(p.Outputs) > 0 {
		outFormats, err := outputFormats.GetByNames(p.Outputs...)
		if err != nil {
			return fmt.Errorf("failed to resolve output formats %v: %w", p.Outputs, err)
		} else {
			p.ConfiguredOutputFormats = outFormats
		}
	}

	return nil
}

// MarkupToMediaType converts a markup string to a media type.
func MarkupToMediaType(s string, mediaTypes media.Types) media.Type {
	s = strings.ToLower(s)
	mt, _ := mediaTypes.GetBestMatch(markup.ResolveMarkup(s))
	return mt
}

type ResourceConfig struct {
	Path    string
	Name    string

View on GitHub (pinned to 52c9bd7908)