YAML and JSON both store structured data, but differ in syntax, readability and use cases. Here's a practical comparison with examples.
What Are YAML and JSON?
JSON (JavaScript Object Notation) and YAML (YAML Ain't Markup Language) are two of the most common formats for structured configuration and data exchange. Both represent the same underlying data — objects, arrays, strings, numbers and booleans — but they present it very differently.
JSON came from JavaScript and is strict, compact and universally supported. YAML was designed for human readability and is common in DevOps tooling like Docker Compose, Kubernetes and CI pipelines.
Syntax Differences at a Glance
- Braces vs indentation: JSON uses
{}and[]; YAML uses indentation and dashes. - Quotes: JSON requires double quotes on keys and string values; YAML usually doesn't.
- Comments: JSON has no comments; YAML supports
#comments. - Trailing commas: illegal in JSON, irrelevant in YAML.
- Data types: YAML infers more types (dates, booleans like
yes/no), which can cause surprises.
When to Use Which
Use JSON for APIs, browser data and anywhere strict parsing and universal support matter. Use YAML for configuration files that humans edit frequently — its comments and cleaner syntax reduce friction.
Many teams author config in YAML and convert to JSON at build time, getting the best of both.
Comparing YAML and JSON Files
Because YAML is a superset of JSON, you can compare them by converting to a common representation. When reviewing a config change, comparing the two versions side by side highlights exactly which keys or values changed — far safer than eyeballing indentation.
A pretty-printing diff tool normalises formatting so you see real content changes, not whitespace noise.
Try It Yourself
Put this into practice with Compares-Text — free, no signup, right in your browser.