What Is YAML?

Definition

YAML (short for "YAML Ain't Markup Language") is a data serialization format designed to be easy for humans to read and write. It represents data as key–value pairs, lists, and nested structures — without the curly braces and brackets that make JSON and XML harder to scan.

name: YAMLTools
private: true
features:
  - browser-based
  - no-upload

Why is YAML so common in configuration?

• Readability: indentation-based structure is easy to review in pull requests.
• Comments: unlike JSON, YAML supports # comments.
• Expressiveness: supports strings, numbers, booleans, lists, and nested maps natively.

Where you meet YAML

• Kubernetes manifests
• Docker Compose files
• GitHub Actions workflows
• CI/CD pipelines and many app config files

Working with YAML

Because YAML is everywhere, converting and validating it is a daily task. Try our YAML to JSON converter, YAML validator, or YAML formatter — all run in your browser, with no upload.