gohugoio/hugo · error

media type %q not found

Error message

media type %q not found

What it means

Thrown by ResourceConfig.Compile when a page resource explicitly sets Content.MediaType but mediaTypes.GetByType returns found=false, meaning that media type string is not registered. This applies to resources (images, data files, etc.) declared in front matter / page resources, not the page content itself.

Source

Thrown at resources/page/pagemeta/page_frontmatter.go:510

	return nil
}

func (rc *ResourceConfig) Compile(basePath string, fim hugofs.FileMetaInfo, conf config.AllProvider, mediaTypes media.Types) error {
	if rc.Params != nil {
		hmaps.PrepareParams(rc.Params)
	}

	// Note that NormalizePathStringBasic will make sure that we don't preserve the unnormalized path.
	// We do that when we create resources from the file system; mostly for backward compatibility,
	// but also because people tend to use the filename to name their resources (with spaces and all),
	// and this isn't relevant when creating resources from an API where it's easy to add textual meta data.
	rc.Path = paths.NormalizePathStringBasic(path.Join(basePath, rc.Path))
	rc.PathInfo = conf.PathParser().Parse(files.ComponentFolderContent, rc.Path)
	if rc.Content.MediaType != "" {
		var found bool
		rc.ContentMediaType, found = mediaTypes.GetByType(rc.Content.MediaType)
		if !found {
			return fmt.Errorf("media type %q not found", rc.Content.MediaType)
		}
	}

	var sitesMatrixFile sitesmatrix.VectorStore
	if fim != nil {
		sitesMatrixFile = fim.Meta().SitesMatrix
	}

	rc.SitesMatrix = buildSitesMatrixFromSitesConfig(
		conf,
		sitesMatrixFile,
		rc.Sites,
	)

	rc.SitesComplements = buildSitesComplementsFromSitesConfig(
		conf,
		fim.Meta(),
		rc.Sites,

View on GitHub (pinned to 52c9bd7908)

Solutions

1. Register the media type under [mediaTypes] in your config.
2. Correct the mediaType string to a known registered type.
3. Omit mediaType and let Hugo infer it from the resource's file extension.

Example fix

# before
---
resources:
  - src: data.custom
    mediaType: application/x-custom
---
# after (also add to config)
[mediaTypes."application/x-custom"]
suffixes = ["custom"]

if _, found := mediaTypes.GetByType(rc.Content.MediaType); rc.Content.MediaType != "" && !found {
    return fmt.Errorf("media type %q not registered", rc.Content.MediaType)
}

if err := rc.Compile(basePath, fim, conf, mediaTypes); err != nil {
    return fmt.Errorf("resource compile: %w", err)
}

When it happens

Trigger: A page resource in front matter sets 'mediaType: application/x-foo' where that type is not defined under [mediaTypes].

Common situations: Referencing a custom media type for a resource without registering it, or a typo in the mediaType value for a resource declaration.

Related errors

• failed to resolve media type for %q
• failed to decode sites from front matter: %w
• failed to resolve media type for suffix %q
• failed to decode page map: %w
• failed to resolve output formats %v: %w

AI-assisted analysis of gohugoio/hugo@52c9bd7908 (2026-08-09). Data as JSON: /api/errors/57c312e0494634ca. Report an issue: GitHub.