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