JSON - Wikipedia Jump to content Main menu Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Contribute Help Learn to edit Community portal Recent changes Upload file Special pages Search Search Appearance Donate Create account Log in Personal tools Donate Create account Log in Contents move to sidebar hide (Top) 1 Naming and pronunciation 2 Standards 3 History 4 Syntax Toggle Syntax subsection 4.1 Character encoding 4.2 Data types 4.3 Comments 4.4 Lint 5 Interoperability Toggle Interoperability subsection 5.1 Semantics 6 Metadata and schema 7 Uses 8 Safety 9 Alternatives Toggle Alternatives subsection 9.1 XML 10 Supersets Toggle Supersets subsection 10.1 YAML 10.2 CSON 10.3 HOCON 10.4 JSON5 10.5 JSONC 11 Derivatives 12 See also 13 Notes 14 References 15 External links Toggle the table of contents JSON 51 languages العربية Azərbaycanca Беларуская Български বাংলা Català Čeština Deutsch Ελληνικά Español Eesti Euskara فارسی Suomi Français Galego עברית हिन्दी Hrvatski Magyar Հայերեն Bahasa Indonesia Ido Italiano 日本語 Qaraqalpaqsha 한국어 Кыргызча Lietuvių Latviešu മലയാളം Bahasa Melayu Nederlands Norsk bokmål Polski Português Română Русский Simple English Slovenščina Shqip Српски / srpski Svenska தமிழ் ไทย Türkçe Українська Oʻzbekcha / ўзбекча Tiếng Việt 粵語 中文 Edit links Article Talk English Read View source View history Tools Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Permanent link Page information Cite this page Get shortened URL Switch to legacy parser Print/export Download as PDF Printable version In other projects Abstract Wikipedia Wikimedia Commons MediaWiki Wikibooks Wikidata item Appearance move to sidebar hide Checked From Wikipedia, the free encyclopedia Page version status This is an accepted version of this page This is the latest accepted revision, reviewed on 16 August 2026. Data-interchange format "Json" redirects here. For people with similar names, see J Son. \n| background color = \n| align = center\n| direction = vertical\n| total_width = 121px\n| image_style = border:none;\n| border = infobox\n| image1 = JSON vector logo.svg\n| alt1 = The JSON logo is a [[Möbius strip]].\n| caption1 = The JSON logo is a [[Möbius strip]].\n}}"},"logo_size":{"wt":"121px"},"logo_caption":{"wt":""},"mime":{"wt":"application/json"},"type_code":{"wt":"TEXT"},"extension":{"wt":".json"},"uniform_type":{"wt":"public.json"},"developer":{"wt":""},"genre":{"wt":"Data interchange"},"extended_from":{"wt":"[[JavaScript]]"},"standard":{"wt":"[https://tools.ietf.org/html/std90 STD 90] ({{IETF RFC|8259}}), [https://ecma-international.org/publications-and-standards/standards/ecma-404/ ECMA-404], [https://www.iso.org/standard/71616.html ISO/IEC 21778:2017]"},"open":{"wt":"Yes"},"url":{"wt":"{{URL|https://json.org/}}"}},"i":0}}]}'>JavaScript Object Notation Möbius strip</a>.","txt":"The JSON logo is a Möbius strip."}]]}'> The JSON logo is a Möbius strip. Filename extension .json Internet media type application/json Type code TEXT Uniform Type Identifier (UTI) public.json Type of format Data interchange Extended from JavaScript Standard STD 90 (RFC 8259), ECMA-404, ISO/IEC 21778:2017 Open format? Yes Website json.org JSON (JavaScript Object Notation, pronounced /ˈdʒeɪsən/ or /ˈdʒeɪˌsɒn/) is an open standard file format and data interchange format that uses human-readable text to store and transmit data objects consisting of name–value pairs and arrays (or other serializable values). It is a commonly used data format with diverse uses in electronic data interchange, including that of web applications with servers. JSON is a programming language-independent data format. It was derived from JavaScript, but many modern programming languages include code to generate and parse JSON-format data. JSON filenames use the extension .json. Douglas Crockford originally specified the JSON format in the early 2000s.[1] He{{cite web|last=Crockford|first=Douglas|author-link=Douglas Crockford|date=December 8, 2022|title=Pronouns|url=https://www.crockford.com/pronouns.html|access-date=February 16, 2026 |quote=My pronouns are 'pe'/'per'.}}</ref> This article uses ''he/him'' for simplicity and understanding. <!-- according to MOS:NEOPRONOUN -->"}},"i":0}}]}'>[a] and Chip Morningstar sent the first JSON message in April 2001. Naming and pronunciation The 2017 international standard (ECMA-404 and ISO/IEC 21778:2017) specifies that "JSON" is "pronounced /ˈdʒeɪ.sən/, as in 'Jason and The Argonauts'".[3][4] The first (2013) edition of ECMA-404 did not address the pronunciation.[5] Crockford said in 2011, "There's a lot of argument about how you pronounce that, but I strictly don't care."[1] /ˈdʒeɪˌsɒn/ is another common pronunciation.[6] Standards After RFC 4627 had been available as its "informational" specification since 2006, JSON was first standardized in 2013, as ECMA-404.[5] RFC 8259, published in 2017, is the current version of the Internet Standard STD 90, and it remains consistent with ECMA-404.[7] That same year, JSON was also standardized as ISO/IEC 21778:2017.[3] The ECMA and ISO/IEC standards describe only the allowed syntax, whereas the RFC covers some security and interoperability considerations.[8] History Douglas Crockford at the Yahoo Building (2007) JSON grew out of a need for a real-time server-to-browser session communication protocol without using browser plugins such as Flash or Java applets, the dominant methods used in the early 2000s.[9] Crockford first specified and popularized the JSON format.[1] The acronym originated at State Software, a company cofounded by Crockford and others in March 2001. The cofounders agreed to build a system that used standard browser capabilities and provided an abstraction layer for Web developers to create stateful Web applications that had a persistent duplex connection to a Web server by holding two Hypertext Transfer Protocol (HTTP) connections open and recycling them before standard browser time-outs if no further data were exchanged. The cofounders had a round-table discussion and voted on whether to call the data format JSML (JavaScript Markup Language) or JSON (JavaScript Object Notation), as well as under what license type to make it available. The JSON.org[10] website was launched in 2001. In December 2005, Yahoo! began offering some of its Web services in JSON.[11] A precursor to the JSON libraries was used in a children's digital asset trading game project named Cartoon Orbit at Communities.com[citation needed] which used a browser side plug-in with a proprietary messaging format to manipulate DHTML elements. Upon discovery of early Ajax capabilities, digiGroups, Noosh, and others used frames to pass information into the user browsers' visual field without refreshing a Web application's visual context, realizing real-time rich Web applications using only the standard HTTP, HTML, and JavaScript capabilities of Netscape 4.0.5+ and Internet Explorer 5+. Crockford then found that JavaScript could be used as an object-based messaging format for such a system. The system was sold to Sun Microsystems, Amazon.com, and EDS. JSON was based on a subset of the JavaScript scripting language (specifically, Standard ECMA-262 3rd Edition—December 1999[12]) and is commonly used with JavaScript, but it is a language-independent data format. Code for parsing and generating JSON data is readily available in many programming languages. JSON's website lists JSON libraries by language. In October 2013, Ecma International published the first edition of its JSON standard ECMA-404.[5] That same year, RFC 7158 used ECMA-404 as a reference. In 2014, RFC 7159 became the main reference for JSON's Internet uses, superseding RFC 4627 and RFC 7158 (but preserving ECMA-262 and ECMA-404 as main references). In November 2017, ISO/IEC JTC 1/SC 22 published ISO/IEC 21778:2017[3] as an international standard. On December 13, 2017, the Internet Engineering Task Force obsoleted RFC 7159 when it published RFC 8259, which is the current version of the Internet Standard STD 90.[7] Crockford added a clause to the JSON license stating, "The Software shall be used for Good, not Evil", in order to open-source the JSON libraries while mocking corporate lawyers and those who are overly pedantic. On the other hand, this clause led to license compatibility problems of the JSON license with other open-source licenses since open-source software and free software usually imply no restrictions on the purpose of use.[13] Syntax The following example shows a possible JSON representation describing a person. { "first_name": "John", "last_name": "Smith", "is_alive": true, "age": 27, "address": { "street_address": "21 2nd Street", "city": "New York", "state": "NY", "postal_code": "10021-3100" }, "phone_numbers": [ { "type": "home", "number": "212 555-1234" }, { "type": "office", "number": "646 555-4567" } ], "children": [ "Catherine", "Thomas", "Trevor" ], "spouse": null } Character encoding Although Crockford originally asserted that JSON is a strict subset of JavaScript and ECMAScript,[14] their specification actually allows valid JSON documents that are not valid JavaScript; JSON allows the Unicode line terminators U+2028 LINE SEPARATOR and U+2029 PARAGRAPH SEPARATOR to appear unescaped in quoted strings, while ECMAScript 2018 and older do not.[15][16] This is a consequence of JSON disallowing only "control characters". For maximum portability, these characters are backslash-escaped. JSON exchange in an open ecosystem must be encoded in UTF-8.[7] The encoding supports the full Unicode character set, including those characters outside the Basic Multilingual Plane (U+0000 to U+FFFF). However, if escaped, those characters must be written using UTF-16 surrogate pairs. For example, to include the Emoji character U+1F610 😐 NEUTRAL FACE in JSON: { "face": "😐" } Or: { "face": "\uD83D\uDE10" } JSON became a strict subset of ECMAScript as of the language's 2019 revision.[16][17] Data types JSON's basic data types are: Number: a signed decimal number that may contain a fractional part and may use exponential E notation but cannot include non-numbers such as NaN. The format makes no distinction between integer and floating-point. JavaScript uses IEEE-754 double-precision floating-point format for all its numeric values (later also supporting BigInt[18]), but other languages implementing JSON may encode numbers differently. String: a sequence of zero or more Unicode characters. Strings are delimited with double quotation marks and support a backslash escaping syntax. Boolean: either of the values true or false Array: an ordered list of zero or more elements, each of which may be of any type. Arrays use square bracket notation with comma-separated elements. Object: a collection of name–value pairs where the names (also called keys) are strings. The current ECMA standard states, "The JSON syntax does not impose any restrictions on the strings used as names, does not require that name strings be unique, and does not assign any significance to the ordering of name/value pairs."[19] Objects are delimited with curly brackets and use commas to separate each pair, while within each pair, the colon ":" character separates the key or name from its value. null: an empty value, using the word null Whitespace is allowed and ignored around or between syntactic elements (values and punctuation, but not within a string value). Four specific characters are considered whitespace for this purpose: space, horizontal tab, line feed, and carriage return. In particular, the byte order mark must not be generated by a conforming implementation (though it may be accepted when parsing JSON…