Data Format Glossary

A comprehensive glossary of JSON, XML, and YAML terminology. Master the vocabulary of data serialization formats.

{ } JSON Terms

JSON

JavaScript Object Notation - a lightweight, text-based data interchange format that is easy for humans to read and write, and easy for machines to parse and generate.

{"name": "John", "age": 30}

Object

An unordered collection of key-value pairs enclosed in curly braces {}. Keys must be strings, and values can be any valid JSON data type.

{"key1": "value1", "key2": "value2"}

Array

An ordered list of values enclosed in square brackets []. Values can be of any type and do not need to be the same type.

[1, "two", true, null]

Key-Value Pair

A fundamental unit in JSON objects consisting of a key (always a string) and a value separated by a colon.

"username": "john_doe"

JSON Schema

A vocabulary that allows you to annotate and validate JSON documents. It describes the structure and constraints of JSON data.

{"type": "object", "properties": {...}}

Serialization

The process of converting a data structure or object into a format (like JSON string) that can be stored or transmitted.

JSON.stringify({a: 1}) → '{"a":1}'

Deserialization

The reverse of serialization - converting a JSON string back into a native data structure or object.

JSON.parse('{"a":1}') → {a: 1}

Minification

The process of removing all unnecessary whitespace and formatting from JSON to reduce file size.

{"a":1,"b":2} (no spaces)

Beautification

The process of adding whitespace, indentation, and line breaks to JSON to make it human-readable.

Pretty-printed JSON with 2-space indent

Nested Object

An object that is a value within another object, creating a hierarchical data structure.

{"user": {"name": "John", "age": 30}}

</> XML Terms

XML

eXtensible Markup Language - a markup language that defines rules for encoding documents in a format that is both human-readable and machine-readable.

<root><item>value</item></root>

Element

The basic building block of XML documents, consisting of a start tag, content, and end tag.

<element>content</element>

Attribute

A name-value pair that provides additional information about an element, placed within the start tag.

Root Element

The single top-level element that contains all other elements in an XML document.

CDATA

Character Data section that tells the parser not to interpret the content as XML markup.

<![CDATA[<not>parsed</not>]]>

DTD

Document Type Definition - defines the structure and legal elements/attributes of an XML document.

<!DOCTYPE root [...]>

XSD

XML Schema Definition - an XML-based alternative to DTD for describing the structure of XML documents.

<xs:schema>...</xs:schema>

Namespace

A collection of element and attribute names identified by a URI, used to avoid naming conflicts.

xmlns:prefix="http://example.com"

XPath

A query language for selecting nodes from an XML document.

/root/element[@id="1"]

XSLT

eXtensible Stylesheet Language Transformations - a language for transforming XML documents into other formats.

<xsl:template match="/">

--- YAML Terms

YAML

YAML Ain't Markup Language - a human-readable data serialization format commonly used for configuration files.

key: value

Scalar

A single value in YAML - can be a string, number, boolean, or null.

name: John

Mapping

YAML equivalent of an object or dictionary - a collection of key-value pairs.

person: name: John age: 30

Sequence

YAML equivalent of an array - an ordered list of items prefixed with dashes.

- item1 - item2 - item3

Indentation

Whitespace at the beginning of lines that defines the structure and hierarchy in YAML. Spaces only, no tabs.

parent: child: value

Anchor

A marker (&name) that allows you to reference the same data elsewhere in the document.

defaults: &defaults adapter: postgres

Alias

A reference (*name) to an anchor, allowing content reuse without duplication.

development: <<: *defaults

Multi-line String

YAML supports multi-line strings using | (literal) or > (folded) block scalars.

description: | Line 1 Line 2

Document Separator

Three dashes (---) that mark the beginning of a YAML document, allowing multiple documents in one file.

--- doc1 --- doc2

Comment

Text preceded by # that is ignored by the parser, used for documentation.

# This is a comment

📚 General Terms

Data Serialization

The process of converting data structures into a format that can be stored or transmitted and reconstructed later.

Object → JSON string → Send → Parse → Object

Parser

A program or function that analyzes a string of symbols according to the rules of a formal grammar.

JSON.parse(), xml2js, yaml.parse()

Validator

A tool that checks if data conforms to a specified format, schema, or set of rules.

JSON Schema validator, XML DTD validator

Encoding

The character set used to represent text. JSON typically uses UTF-8 encoding.

UTF-8, UTF-16, ASCII

API

Application Programming Interface - a set of rules for building and interacting with software. REST APIs commonly use JSON.

GET /api/users returns JSON

Put Your Knowledge to Practice

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