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JSON vs YAML

JSON vs YAML

JSON vs YAML compared — syntax, readability, comments, data types and speed, plus when to use each and free tools to convert between them.

JSON and YAML both describe structured data, and YAML is actually a superset of JSON — every JSON document is valid YAML. The difference is ergonomics: JSON uses explicit braces and brackets and is ubiquitous in APIs, while YAML uses indentation and is favoured for human-edited config files.

JSON vs YAML at a glance

	JSON	YAML
Syntax	Braces {} and brackets [], quoted keys	Indentation, minimal punctuation
Comments	Not supported	Supported with #
Readability	Compact, machine-friendly	Human-friendly for config
Data types	Strings, numbers, bool, null, array, object	Same + anchors, references, multi-line strings
Parsing	Fast, everywhere	Slower, indentation-sensitive
Typical use	APIs, web payloads	CI/CD, Kubernetes, app config

When to use JSON

Choose JSON for API responses and data interchange — it is faster to parse, supported everywhere, and unambiguous. If a machine reads it, JSON is usually the safer default.

When to use YAML

Choose YAML for files humans edit by hand — CI pipelines, Docker Compose, Kubernetes manifests — where comments and clean indentation matter more than parse speed.