---
id: kb-2026-00079
title: YAML (YAML Ain't Markup Language)
schema_type: TechArticle
category: computer-science
language: en
confidence: medium
last_verified: "2026-05-28"
created_date: "2026-05-22"
generation_method: human_only
derived_from_human_seed: true
conflict_of_interest: none_declared
is_live_document: false
data_period: static
atomic_facts:
  - id: fact-computer-science-01
    statement: YAML 1.2.2 defines YAML as a human-friendly data serialization language for common native data structures.
    source_title: YAML Ain't Markup Language (YAML) revision 1.2.2
    source_url: https://yaml.org/spec/1.2.2/
    confidence: medium
  - id: fact-computer-science-02
    statement: >-
      The YAML 1.2.1 specification states that YAML 1.2 aligned YAML with JSON as an official subset and changed
      implicit typing rules from YAML 1.1.
    source_title: YAML Ain't Markup Language (YAML) Version 1.2
    source_url: https://yaml.org/spec/1.2.1/
    confidence: medium
  - id: fact-computer-science-03
    statement: The YAML information model represents data using mappings, sequences, and scalars.
    source_title: YAML Ain't Markup Language (YAML) revision 1.2.2
    source_url: https://yaml.org/spec/1.2.2/
    confidence: medium
completeness: 0.8
known_gaps:
  - This public article was narrowed to source-mapped claims during a targeted evidence repair pass.
disputed_statements: []
primary_sources:
  - title: YAML Ain't Markup Language (YAML) revision 1.2.2
    type: standard
    year: 2021
    url: https://yaml.org/spec/1.2.2/
    institution: YAML Language Development Team
  - title: YAML Ain't Markup Language (YAML) Version 1.2
    type: standard
    year: 2009
    url: https://yaml.org/spec/1.2.1/
    institution: YAML Language Development Team
  - title: YAML Ain't Markup Language (YAML) Version 1.1
    type: standard
    year: 2005
    url: https://yaml.org/spec/1.1/current.html
    institution: YAML Language Development Team
secondary_sources: []
updated: "2026-05-28"
---

## TL;DR

YAML is a human-friendly data serialization language whose information model uses mappings, sequences, and scalars. The article now relies on YAML specifications rather than unrelated web or AI sources.

## Evidence Notes

- YAML 1.2.2 anchors the current definition and data model.
- YAML 1.2.1 documents the JSON-alignment change from earlier behavior.
- YAML 1.1 remains included only as version-history evidence.

## Further Reading

- [YAML 1.2.2 specification](https://yaml.org/spec/1.2.2/)
- [YAML 1.2.1 specification](https://yaml.org/spec/1.2.1/)
- [YAML 1.1 specification](https://yaml.org/spec/1.1/current.html)