YAML (YAML Ain't Markup Language)

YAML is a human-friendly data serialization language that uses indentation to represent structure. It is the preferred format for configuration files in DevOps tools (Docker Compose, Kubernetes, Ansible, GitHub Actions) and is a superset of JSON.

MIME Type

application/x-yaml

Type

Text

Compression

Lossless

Advantages

+ Highly readable — minimal syntax noise
+ Supports comments for inline documentation
+ Native in Docker, Kubernetes, Ansible, and CI/CD systems
+ Superset of JSON — any JSON is valid YAML

Disadvantages

− Indentation-sensitive — whitespace errors cause silent failures
− Implicit type coercion can cause bugs ('yes' becomes boolean true)
− More complex specification than JSON with anchors, tags, and directives

When to Use .YAML

Use YAML for configuration files, CI/CD pipelines, container orchestration, and any human-edited structured data.

Technical Details

YAML uses indentation (spaces, not tabs) for nesting, colons for key-value pairs, and hyphens for list items. It supports anchors (&) and aliases (*) for data reuse, multi-line strings, and comments.

History

Clark Evans, Ingy dot Net, and Oren Ben-Kiki created YAML in 2001. The recursive name stands for 'YAML Ain't Markup Language.' YAML 1.2 (2009) aligned the specification as a JSON superset.

Convert from .YAML

.yaml → .csv .yaml → .json .yaml → .ndjson .yaml → .sql .yaml → .toml .yaml → .tsv .yaml → .xml .yaml → .yml

Convert to .YAML

.csv → .yaml .json → .yaml .ndjson → .yaml .sql → .yaml .toml → .yaml .tsv → .yaml .xml → .yaml .yml → .yaml

Related Formats

.c .cpp .css .csv .go .java .js .json .jsx .less

Related Terms

YAML

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