Serialization

How is it written down?

tension: Formal precision against developer familiarity: RDF/XML against JSON-LD.
also: Syntax, Concrete syntax, Data format
scheme: design issues

Threads (2)

Long-running problems under this issue, told step by step. All threads.

Rigour against developer taste 1998–2015 largely settled 10 steps
What does a data format have to look like before ordinary web developers will use it?
Can ordinary developers use it? 1987–2024 open 12 steps
Can people who are not specialists build with linked data, or does it stay a tool for experts?

Who answered it

This issue's row of the map: which traditions' works mainly answer it, and the earliest from each.

Works on this issue by tradition
tradition	works	earliest
Hypertext	1	Text Encoding Initiative 1987
Knowledge representation
Databases
Machine learning
Web standards	10	XML 1998
Search	2	RSS 1999
Social web	2	RSS 1999
Open knowledge
Decentralized web	1	CBOR-LD 2026
Libraries, archives and museums	4	MARC 1965
Life sciences
Media
Geospatial	2	Two-line element set 1980
Commerce and supply chain	1	UN/EDIFACT 1987
Government and law	1	Akoma Ntoso 2004
Finance
Industry and engineering

9 of 17 traditions have taken up this question as a work's main issue; a work in several traditions counts in each. Same counts as the full map.

Timeline

Works on this question, its main or a secondary one, each shown once in date order; filter by tradition to follow one community. Bars run from start to end where both are known; marks people, projects and organizations still active. 1 entry has no date and is not shown. Hover over or focus an entry to draw its links. Scroll sideways, or use the decades above.

Lineage (17)

Works whose main question this is, by type, oldest first.

Concepts 1

Embedded structured data concept technique
Machine-readable data inside ordinary HTML pages, written as microformats, RDFa, microdata or JSON-LD and usually using the schema.org vocabulary.

Standards 16

MARC 1965 standard ★ seminal
MAchine-Readable Cataloging: formats for library catalogue records, developed by Henriette Avram at the Library of Congress between 1965 and 1968 so that libraries could share records by computer; a US national standard by 1971 and international by 1973. MARC 21 (1999) is still the predominant format.
Two-line element set 1980 standard
NORAD's fixed-width text format for an object's orbit, read with the SGP4 model published in 1980; still the most shared orbital data, though its five-digit catalogue field overflowed and the CCSDS Orbit Mean-Elements Message has been used alongside it since 2020.
Text Encoding Initiative 1987 standard ★ seminal
Guidelines for encoding texts for scholarly study, from a 1987 meeting of humanities and computing scholars at Vassar College; P3 appeared in 1994, P4 moved to XML in 2002 and P5 followed in 2007. It is the standard markup of the digital humanities.
UN/EDIFACT 1987 standard
The UN's standard messages and syntax for electronic data interchange between businesses, such as orders and invoices, approved as ISO 9735 in 1987 after merging with the American proposals: machine-readable business documents a decade before the Web.
Encoded Archival Description 1998 standard
Markup standard for archival finding aids, begun at Berkeley in the early 1990s and released in 1998; it is maintained by the Society of American Archivists and the Library of Congress, with EAD3 from 2015.
XML 1998 standard ★ seminal
W3C markup language for structured documents and data, a Recommendation since February 1998; RDF's first official syntax was written in it.
RSS 1999 standard ★ seminal
Family of XML formats for syndicating site updates. Netscape's RSS 0.90 (1999) and RSS 1.0 were RDF-based; RSS 2.0 is plain XML.
Akoma Ntoso 2004 standard
XML standard for legislative, judicial and executive documents, begun in 2004 by the UN for African parliaments and adopted by OASIS as LegalDocML in August 2018; its identifiers follow the FRBR model of work, expression and manifestation.
Microformats 2005 standard ★ seminal
Conventions for marking up people, events, reviews and similar data with plain HTML class names, without a separate data format.
GeoJSON 2008 standard
JSON format for geographic features, first specified by a community group in 2008 and standardised as RFC 7946 in August 2016, which dropped other coordinate systems in favour of WGS 84 alone; the developers' favourite, with no RDF in it.
RDFa 2008 standard
W3C syntax for embedding RDF statements in HTML attributes, first a Recommendation in October 2008.
HTML microdata 2009 standard
Attributes for nesting machine-readable data in HTML, added to the WHATWG's HTML specification in 2009 as a simpler alternative to RDFa and microformats; schema.org launched with it in 2011.
CBOR 2013 standard
IETF binary data format with a data model close to JSON's, designed for small code and message size on constrained devices; first published as RFC 7049 in October 2013 and revised as Internet Standard RFC 8949 in December 2020.
JSON-LD 2014 standard ★ seminal
JSON-based syntax for Linked Data that lets ordinary JSON be read as RDF; a W3C Recommendation since January 2014.
Turtle 2014 standard
Compact text syntax for writing RDF triples by hand, widely used long before it became a W3C Recommendation in February 2014.
CBOR-LD 2026 standard
Binary serialization of JSON-LD in CBOR that uses JSON-LD contexts to compress terms and values, reporting results more than 60% better than general-purpose compression; meant for storage- and bandwidth-constrained settings. A W3C JSON-LD Working Group First Public Working Draft since 28 April 2026.

Also bears on this (10)

Writings 1

Meta Content Framework Using XML 1997 writing ★ seminal
1997 submission to the W3C by R.V. Guha and Tim Bray describing MCF in XML; a direct precursor to RDF.

Standards 8

HTML 1991 standard ★ seminal
HyperText Markup Language, the markup of Web pages, whose anchor element carries the Web's links. Berners-Lee first described it in the informal 'HTML Tags' document in late 1991; HTML 2.0 was published as RFC 1866 in November 1995.
STEP 1994 standard
ISO's family of standards for describing manufactured products so CAD, manufacturing and archive systems can exchange them, begun in 1984 and first published in 1994–95; its EXPRESS schema language is an early example of a formal shared data model across an industry.
Meta Content Framework 1995 standard
Format for describing the structure and metadata of websites, developed by R.V. Guha at Apple and later submitted to the W3C with Tim Bray as an XML application.
SHOE c. 1996 standard
Simple HTML Ontology Extensions: an early language for writing ontologies and annotating web pages with machine-readable claims, developed at the University of Maryland around 1996; among the first ontology languages made for the Web.
XBRL 1998 standard
Format for business and financial reports whose taxonomies define each reporting concept and its relations, begun by Charles Hoffman in 1998; regulators, securities commissions and tax agencies worldwide receive filings in it, and Inline XBRL embeds the tags in an ordinary HTML report.
Open Graph protocol 2010 standard
Facebook's 2010 vocabulary of meta tags that turn a web page into a rich object when shared; the first version was based on RDFa.
Activity Streams 2.0 2017 standard
W3C vocabulary and JSON-LD format for describing social activities such as posts, likes and follows; a Recommendation since May 2017.
RDF Dataset Canonicalization 2024 standard
W3C algorithm that gives any RDF dataset a single canonical form, so the same graph always hashes and signs the same way regardless of blank-node labels or order; a Recommendation since May 2024.

Projects 1

Web Data Commons 2012 project
Project that extracts microdata, RDFa, JSON-LD and microformats data from the Common Crawl web corpus and publishes it for research.

People and organizations (39)

Linked to works on this question; the number counts those works.

World Wide Web Consortium (5) · C. M. Sperberg-McQueen (2) · Dave Longley (2) · Library of Congress (2) · Manu Sporny (2) · Aaron Swartz · Allan Doyle · Ben Adida · Dan Libby · Daniel Pitti · David Beckett · Eric Prud'hommeaux · Fabio Vitali · Gavin Carothers · Gregg Kellogg · Henriette Avram · Howard Butler · Jean Paoli · Kevin Marks · Lou Burnard · Mark Birbeck · Markus Lanthaler · Martin Daly · Monica Palmirani · Netscape · Niklas Lindström · Pierre-Antoine Champin · R.V. Guha · Sean Gillies · Shane McCarron · Stefan Hagen · Steven Pemberton · Tantek Çelik · Tim Berners-Lee · Tim Bray · Tim Schaub · UN/CEFACT · Wesley Smith · WHATWG