The EPUB package document (OPF)

The package document, usually named content.opf or package.opf, is the centre of an EPUB: container.xml points to it, and it lists the book’s metadata, every file in it and the reading order. It is XML in the namespace http://www.idpf.org/2007/opf, with media type application/oebps-package+xml. Relative URLs in it are resolved from the package document’s own folder. This page follows EPUB 3.3; the last section lists what differs in EPUB 2 (OPF 2.0.1).

package

The root element. Its children, in this order: metadata (one), manifest (one), spine (one), guide (optional, legacy), bindings (optional, deprecated), collection (any number).

Attribute	Status	Meaning
`version`	Required	`3.0` for every EPUB 3 version (3.0, 3.0.1, 3.2, 3.3); `2.0` for EPUB 2. This is the only reliable way to tell the versions apart.
`unique-identifier`	Required	The `id` of the `dc:identifier` that identifies the book, also used as the key for font obfuscation.
`prefix`	Optional	Declares prefixes for property vocabularies, as pairs: `prefix="foaf: http://xmlns.com/foaf/spec/"`. See prefixes.
`xml:lang`	Optional	The language of the package’s text.
`dir`	Optional	Text direction of the package’s text: `ltr`, `rtl` or `auto`.
`id`	Optional	An ID.

metadata

Holds Dublin Core elements (namespace http://purl.org/dc/elements/1.1/, prefix dc), meta elements and link elements. Three Dublin Core elements and one meta are required.

Element	Number	Attributes	Meaning
`dc:identifier`	1 or more	`id`	An identifier: a UUID (`urn:uuid:…`), ISBN (`urn:isbn:…`), DOI and so on. The one named by `unique-identifier` must have an `id`.
`dc:title`	1 or more	`dir`, `id`, `xml:lang`	A title. The first is the main title; others can be typed with `title-type`.
`dc:language`	1 or more	`id`	A language of the content, as a BCP 47 tag such as `en-GB`.
`meta property="dcterms:modified"`	Exactly 1		When the book was last changed, as `CCYY-MM-DDThh:mm:ssZ` in UTC. With the unique identifier it identifies this exact release.
`dc:contributor`	Any	`dir`, `id`, `xml:lang`	Someone who contributed in a secondary role.
`dc:coverage`	Any	same	The place or time the content covers.
`dc:creator`	Any	same	An author or other main creator, in display order.
`dc:date`	At most 1	`id`	The publication date, in W3C date format (`2026`, `2026-11`, `2026-11-12`…).
`dc:description`	Any	`dir`, `id`, `xml:lang`	A description.
`dc:format`	Any	`id`	The format; rarely used.
`dc:publisher`	Any	`dir`, `id`, `xml:lang`	The publisher.
`dc:relation`	Any	same	A related resource.
`dc:rights`	Any	same	A rights statement.
`dc:source`	Any	`id`	The work this one is derived from, such as the printed edition’s ISBN.
`dc:subject`	Any	`dir`, `id`, `xml:lang`	A subject, optionally coded with `authority` and `term`.
`dc:type`	Any	`id`	The nature of the content, such as `dictionary` or `index`.

meta

A meta element states one property. Its text is the value.

Attribute	Meaning
`property`	Required. The property, from the vocabulary below or from a prefixed vocabulary (`dcterms:modified`, `schema:accessMode`…).
`refines`	Optional. `#id` of the element or resource this statement is about. Without it, the statement is about the whole publication.
`scheme`	Optional. The system the value is taken from, such as `marc:relators`.
`id`, `dir`, `xml:lang`	Optional. ID, text direction and language.

Meta properties

Properties without a prefix come from the package’s default meta vocabulary (http://idpf.org/epub/vocab/package/meta/#):

Property	Refines	Value
`alternate-script`	any	The value of the refined element in another script or language, such as an author’s name in Japanese; carries its own `xml:lang`.
`authority`	`dc:subject`	The subject scheme, such as `BISAC` or a URL; at most one.
`belongs-to-collection`	publication or another collection	The name of a series or set the book belongs to.
`collection-type`	`belongs-to-collection`	`series` (published in order, possibly open-ended) or `set` (a finite group).
`display-seq`	any	The order in which repeated elements should be displayed: a whole number.
`file-as`	any	A sort form, such as `Wells, H. G.`.
`group-position`	`belongs-to-collection` and others	The position in the collection: a number or dotted numbers such as `2.2.1`.
`identifier-type`	`dc:identifier`, `dc:source`	The identifier’s type, usually as an ONIX code with `scheme="onix:codelist5"` (for example `15` for ISBN-13).
`meta-auth`	–	Deprecated. Who supplied the metadata.
`role`	`dc:creator`, `dc:contributor`, `dc:publisher`	The role, usually a MARC relator code with `scheme="marc:relators"`: `aut` author, `edt` editor, `ill` illustrator, `trl` translator, `nrt` narrator and so on.
`source-of`	`dc:source`	`pagination`: the page numbers in the book come from this source.
`term`	`dc:subject`	The subject’s code in the scheme given by `authority`.
`title-type`	`dc:title`	`main`, `subtitle`, `short`, `collection`, `edition` or `expanded`.

Other properties found in packages come from the reserved prefixes: Media Overlays (media:duration, media:narrator, media:active-class, media:playback-active-class), fixed layout (rendition:layout, rendition:orientation, rendition:spread, rendition:flow, rendition:viewport (deprecated)) — see content and layout — and accessibility metadata from schema.org (schema:accessMode, schema:accessModeSufficient, schema:accessibilityFeature, schema:accessibilityHazard, schema:accessibilitySummary) and the a11y: vocabulary (a11y:certifiedBy, a11y:certifierCredential, a11y:certifierReport, a11y:exemption).

link

Points to a resource about the publication, such as a metadata record.

Attribute	Meaning
`href`	Required. The resource, in the container or remote.
`rel`	Required. Space-separated relationships: see below.
`media-type`	Required when the resource is in the container.
`properties`	Optional. `onix`: the record is an ONIX record.
`refines`	Optional. What the link is about, as `#id`.
`hreflang`, `id`	Optional. The resource’s language; an ID.

`rel` value	Meaning
`alternate`	An alternate form of the publication or of a resource, such as a PDF; used with other rels.
`record`	A metadata record for the publication (ONIX, MARC and so on, told apart by `media-type` and `properties`).
`voicing`	An audio recording of how to pronounce the refined element, such as an author’s name.
`marc21xml-record`, `mods-record`, `onix-record`, `xml-signature`, `xmp-record`	Deprecated forms of `record` and of a signature link.

manifest

Lists every file of the publication except mimetype, the META-INF files and the package document itself, with one item each. Remote resources (audio, video, fonts) that are part of the rendering are listed too.

Attribute	Status	Meaning
`id`	Required	The item’s ID, used by the spine and by `fallback`.
`href`	Required	The file, relative to the package document.
`media-type`	Required	Its MIME type. Types outside the core media types need a fallback.
`fallback`	When needed	The `id` of an item to use instead when the reading system does not support this one; chains may be several items long and must end in a core type.
`properties`	Optional	Space-separated properties: see below.
`media-overlay`	Optional	The `id` of the SMIL media overlay that goes with this content document.

Item properties

Property	Meaning
`cover-image`	The cover image. At most one item.
`mathml`	The document contains MathML.
`nav`	The navigation document. Exactly one item.
`remote-resources`	The document refers to resources outside the container.
`scripted`	The document contains scripts or forms.
`svg`	The document contains SVG (inline or in a `foreignObject`).
`switch`	The document uses `epub:switch` (deprecated).

spine

The reading order: one itemref per content document, in order. At least one must be linear.

Element	Attribute	Meaning
`spine`	`page-progression-direction`	`ltr`, `rtl` or `default` (the default): the direction pages turn, for example `rtl` for Japanese manga.
`spine`	`toc`	Legacy: the `id` of the NCX item. Required in EPUB 2.
`spine`	`id`	An ID.
`itemref`	`idref`	Required: a manifest item’s `id`. Each item at most once.
`itemref`	`linear`	`yes` (default) or `no`: auxiliary content, such as notes or answers, that is reached by links rather than by turning pages.
`itemref`	`properties`	Space-separated: see below.
`itemref`	`id`	An ID.

Itemref properties

Property	Meaning
`page-spread-left`, `page-spread-right`	In a two-page spread, put this page on the left or right.
`rendition:page-spread-center`	Show this page alone, centred, across the spread.
`rendition:layout-pre-paginated`, `rendition:layout-reflowable`	Override the global layout for this document.
`rendition:orientation-auto`, `-landscape`, `-portrait`	Override the orientation.
`rendition:spread-auto`, `-both`, `-landscape`, `-none`, `-portrait` (deprecated)	Override when spreads are shown.
`rendition:flow-auto`, `-paginated`, `-scrolled-continuous`, `-scrolled-doc`	Override the overflow behaviour.
`rendition:align-x-center`	Centre the content horizontally.

collection

Groups resources for a purpose: role (required) names the purpose, as a token or an absolute URL; id, dir and xml:lang are optional. A collection holds an optional metadata, then nested collection elements and link elements to its members. Roles have been defined by separate specifications, such as index and dictionary; the EPUB 3.3 specification deprecates making new ones.

guide and bindings

guide (legacy, from EPUB 2) lists landmarks as reference elements with type, title and href; EPUB 3 replaces it with the landmarks nav, and its type values are listed there.

bindings (deprecated) maps a media type to a scripted handler: mediaType elements with media-type and handler attributes.

Reserved prefixes

These prefixes may be used without declaring them in prefix:

Prefix	URL
`a11y`	`http://www.idpf.org/epub/vocab/package/a11y/#`
`dcterms`	`http://purl.org/dc/terms/`
`marc`	`http://id.loc.gov/vocabulary/`
`media`	`http://www.idpf.org/epub/vocab/overlays/#`
`onix`	`http://www.editeur.org/ONIX/book/codelists/current.html#`
`rendition`	`http://www.idpf.org/vocab/rendition/#`
`schema`	`http://schema.org/`
`xsd`	`http://www.w3.org/2001/XMLSchema#`

In content documents, msv and prism are also reserved for epub:type values.

Example

<?xml version="1.0" encoding="UTF-8"?>
<package xmlns="http://www.idpf.org/2007/opf" version="3.0"
         unique-identifier="uid" xml:lang="en">
  <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
    <dc:identifier id="uid">urn:uuid:4f3c2b1a-1111-4c2d-8e9f-0a1b2c3d4e5f</dc:identifier>
    <dc:title>The Time Machine</dc:title>
    <dc:creator id="au">H. G. Wells</dc:creator>
    <meta refines="#au" property="role" scheme="marc:relators">aut</meta>
    <meta refines="#au" property="file-as">Wells, H. G.</meta>
    <dc:language>en-GB</dc:language>
    <meta property="dcterms:modified">2026-11-12T09:00:00Z</meta>
  </metadata>
  <manifest>
    <item id="nav" href="nav.xhtml" media-type="application/xhtml+xml" properties="nav"/>
    <item id="cover" href="images/cover.jpg" media-type="image/jpeg" properties="cover-image"/>
    <item id="css" href="style.css" media-type="text/css"/>
    <item id="c1" href="chapter1.xhtml" media-type="application/xhtml+xml"/>
    <item id="notes" href="notes.xhtml" media-type="application/xhtml+xml"/>
  </manifest>
  <spine>
    <itemref idref="c1"/>
    <itemref idref="notes" linear="no"/>
  </spine>
</package>

Differences in EPUB 2 (OPF 2.0.1)

version="2.0".
Metadata is refined with attributes in the OPF namespace instead of meta refines: opf:role and opf:file-as on dc:creator and dc:contributor, opf:scheme on dc:identifier (such as ISBN or UUID), opf:event on dc:date (creation, publication, modification). dc:date may repeat.
meta has the form <meta name="…" content="…"/>; the cover image is named by <meta name="cover" content="item id"/>, a convention many EPUB 3 books keep for older readers.
dcterms:modified, link, item and itemref properties, media-overlay, collection and the rendition properties do not exist.
The table of contents is an NCX file, named by spine toc, which is required.
The guide is the way to mark landmarks.
Content documents are XHTML 1.1 or DTBook, styled with a subset of CSS 2; an out-of-line XML island (ops:switch) and tours exist but were rarely used.

.EPUB File Format – Package document