hAtom 0.1

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This document represents a draft microformat specification. Although drafts are somewhat mature in the development process, the stability of this document cannot be guaranteed, and implementers should be prepared to keep abreast of future developments and changes. Watch this wiki page, or follow discussions on the #microformats Freenode IRC channel to stay up-to-date.

hAtom is a microformat for content that can be syndicated, primarily but not exclusively weblog postings. hAtom is based on a subset of the Atom syndication format. hAtom will be one of several microformats open standards.


Draft Specification

David Janes (BlogMatrix, Inc.)
Benjamin Carlyle
Tantek Çelik (http://tantek.com/ and before at Technorati, Inc.)

copyright and patents statements apply.


hAtom 0.1 is a microformats.org draft specification. Public discussion on hAtom takes place on hatom-feedback, the #microformats irc channel on irc.freenode.net, and microformats-discuss mailing list.

Available languages

The English version of this specification is the only normative version. For translations of this document see the #translations section.

Errata and Updates

Known errors and issues in this specification are corrected in resolved and closed issues. Please check there before reporting issues.

The hAtom 0.2 update is currently under development and incorporates known errata corrections as well as the value-class-pattern.


hAtom is a microformat for identifying semantic information in weblog posts and practically any other place Atom may be used, such as news articles. hAtom content is easily added to most blogs by simple modifications to the blog's template definitions.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.


Here is a simple blog post example:

<article class="hentry">
  <h1 class="entry-title">Microformats are amazing</h1>
  <p>Published by <span class="author vcard"><span class="fn">W. Developer</span></span>
     on <time class="published" datetime="2013-06-13 12:00:00">13<sup>th</sup> June 2013</time>
  <p class="entry-summary">In which I extoll the virtues of using microformats.</p>
  <div class="entry-content">
    <p>Blah blah blah</p>

Get started

The class hentry is a root class name that indicates the presence of an hAtom entry.

entry-title, author, published, entry-summary, entry-content and the other hAtom property classnames listed below define properties of the entry.


In General

The Atom Syndication Format provides the conceptual basis for this microformat, with the following caveats:


Schema elements are based on the Atom nomenclature and follow the microformat pattern of prefixing a unique identifier (in this case, 'h') on the outermost container elements -- the Feed or Entry. The parts of this microformat are based on analysis of many weblog, bulletin board and media posts and can be read blog-post-brainstorming#Discovered_Elements.

The hAtom schema consists of the following:

[*] Some required elements have defaults if missing, see below.

Field and Element Details

Feed Category
This allows quoting other microformated data without worry of corrupting the model
Entry Category
Entry Title
Entry Content
Many web logs split content into multiple sections with a "Read More" link and JavaScript tricks. This is also needed in cases where Entry Titles are coded in-line and are considered part of the content.
Entry Summary
Entry Permalink
Entry Updated
Entry Published
Entry Author

XMDP Profile

See hatom-profile.


See hatom-examples.

Examples in the wild

See hatom-examples-in-wild.


See hatom-implementations.


This specification is (C) 2005-2022 by the authors. However, the authors intend to submit (or already have submitted, see details in the spec) this specification to a standards body with a liberal copyright/licensing policy such as the GMPG, IETF, and/or W3C. Anyone wishing to contribute should read their copyright principles, policies and licenses (e.g. the GMPG Principles) and agree to them, including licensing of all contributions under all required licenses (e.g. CC-by 1.0 and later), before contributing.


This specification is subject to a royalty free patent policy, e.g. per the W3C Patent Policy, and IETF RFC3667 & RFC3668.

Semantic HTML Design Principles

  1. Reuse the schema (names, objects, properties, values, types, hierarchies, constraints) as much as possible from pre-existing, established, well-supported microformats.
  2. When new schema are needed, reuse the schema (names, objects, properties, values, types, hierarchies, constraints) as much as possible from pre-existing, established, well-supported other formats/standards by incorporation, following the microformats naming-principles. Re-do constraints expressed in the source standard from the perspective of microformats design principles and designed primarily for web authoring. Informatively mention source standard for reference purposes.
    1. For types with multiple components, use nested elements with class names equivalent to the names of the components.
    2. Plural components are made singular, and thus multiple nested elements are used to represent multiple text values that are comma-delimited.
  3. Use the most accurately precise semantic HTML building block for each object etc.
  4. Otherwise use a generic structural element (e.g. <span> or <div>), or the appropriate contextual element (e.g. an <li> inside a <ul> or <ol>).
  5. Use class names based on names from the original schema, unless the semantic HTML building block precisely represents that part of the original schema. If names in the source schema are case-insensitive, then use an all lowercase equivalent. Components names implicit in prose (rather than explicit in the defined schema) should also use lowercase equivalents for ease of use. Spaces in component names become dash '-' characters.
  6. Finally, if the format of the data according to the original schema is too long but still human readable/listenable, use <abbr> instead of a generic structural element, and place the literal longer data into the 'title' attribute (where abbr expansions go), and the briefer equivalent into the contents of the element itself. If however, the format of the literal longer data data is not human-friendly, instead of <abbr>, use the value-class-pattern or HTML5 <time>/<data> elements as most semantically appropriate.


Normative References

Informative References

Further Reading

Work in progress

This specification is a work in progress. As additional aspects are discussed, understood, and written, they will be added. There is a separate document where we are keeping our brainstorms and other explorations relating to hAtom:

Version 0.1

Version 0.1 was released 28 February 2006.




See Also


Read the hAtom draft specification in additional languages:


hAtom 0.1 was last modified: Sunday, August 25th, 2013