# EPUBCheck OPF-094: link needs a media type, how to fix it

Source: https://epubcc.com/epubcheck/opf-094/ (updated 2026-11-04)

EPUBCheck OPF-094 is an error message: “The "media-type" attribute is required for "…" links.” A metadata link of a type that requires a media type has none. EPUB requires media-type on record and voicing links, and EPUBCheck names the rel value.

- Official message (EPUBCheck 5.4.0): The "media-type" attribute is required for "%1$s" links.
- Default severity: Error

## Typical causes

- A rel="record" link to an external metadata record without media-type.
- A rel="voicing" link to an audio file without media-type.
- A link copied from an example that left the attribute out.

## How to fix it

1. Find the link element EPUBCheck points to.
2. Add media-type with the real format of the linked file, for example media-type="application/xml" for a record or media-type="audio/mpeg" for an MP3 voicing.
3. For a record whose format the media type does not identify, also add an identifying property such as properties="onix".

## When it's not this

If the link is a voicing link with a non-audio media type, that is OPF-095.

## Sources

- EPUB 3.3, §D.4.1.5 record: https://www.w3.org/TR/epub-33/#sec-record (read 2026-11-04)
- EPUB 3.3, §D.4.1.6 voicing: https://www.w3.org/TR/epub-33/#sec-voicing (read 2026-11-04)

Message text and severity: EPUBCheck (W3C, BSD-3-Clause). Explanation: EpubCC.