Reference

YAML

YAML is a human-readable, text-based data format that uses indentation instead of brackets to show structure. It is popular for configuration files because it is easy to read and write by hand, and it is a superset of JSON.

Files & formatsGeneral

YAML

Also known as: YAML file, .yaml, .yml, YAML Ain't Markup Language

Uses indentation instead of brackets for structure
Common for configuration and CI/CD files
A human-friendly superset of JSON

Why YAML is used for config

YAML expresses the same key/value and list structures as JSON, but relies on line breaks and indentation rather than braces and commas. The result reads almost like a plain outline, which is why tools, CI pipelines, and app settings often ship `.yaml` or `.yml` files.

Because spacing defines the structure, indentation has to be consistent — a single misaligned line can change what a file means.

YAML vs JSON

YAML is a superset of JSON, so any JSON is valid YAML, but YAML adds comments, multi-line strings, and a cleaner syntax for humans. JSON stays better for data sent between programs, where strictness and speed matter more than readability.

Related terms

Keep reading the reference.

Files & formatsJSONJSON (JavaScript Object Notation) is a lightweight, text-based format for storing and exchanging structured data as key/value pairs and ordered lists. It is human-readable, language-independent, and the default format for most web APIs and config files.General Files & formatsXMLXML (Extensible Markup Language) is a text-based format that stores structured data inside nested, custom-named tags, such as `<title>…</title>`. It is self-describing and widely used for documents, configuration, RSS feeds, and data exchange between systems.General Files & formatsINI fileAn INI file (`.ini`) is a simple plain-text configuration format that stores settings as `key=value` pairs, optionally grouped under `[section]` headers. It is easy to read and edit, and is common for app and Windows settings.GeneralWindows Files & formatsPlain text (.txt)A plain-text file (`.txt`) contains only unformatted text — characters with no fonts, colors, images, or layout. It is the simplest, most universal document format, readable by virtually any device or program.General