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JSON vs YAML

Comparing JavaScript Object Notation and YAML Ain't Markup Language - which format should you use?

	JSON	YAML
Full Name	JavaScript Object Notation	YAML Ain't Markup Language
Extension	.json	.yml
MIME Type	application/json	application/x-yaml
Category	data	data

JSON Pros

+Human-readable and writable
+Native support in every programming language
+Lightweight and fast to parse
+The standard for web APIs

JSON Cons

-No comments allowed in standard JSON
-No date type (dates stored as strings)
-No support for binary data
-Large files with deeply nested structures

YAML Pros

+Very human-readable
+Supports comments (JSON doesn't)
+Less verbose than JSON or XML
+Widely used in DevOps (Docker, Kubernetes, GitHub Actions)

YAML Cons

-Indentation-sensitive (tabs vs spaces cause errors)
-Implicit typing can cause surprises ('yes' becomes boolean true)
-Not as fast to parse as JSON
-Complex features (anchors, aliases) are confusing

Use JSON when...

-REST API request/response data
-Configuration files
-Data storage and exchange
-Web application state management

Use YAML when...

-Docker Compose files
-Kubernetes manifests
-GitHub Actions workflows
-CI/CD pipeline configs
-Ansible playbooks

Learn more about JSON Learn more about YAML