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.
Tools for JSON & YAML
JSON Formatter
Format, validate, and minify JSON online. Free, no signup — your data never leaves your browser.
Open toolYAML Formatter & Validator
Validate, reformat, and minify YAML in your browser. Catches syntax errors with line numbers.
Open toolJSON to YAML Converter
Convert JSON to YAML in your browser. YAML 1.2 spec.
Open toolYAML to JSON Converter
Convert YAML to JSON in your browser. Catches syntax errors with parser messages.
Open toolJSON vs YAML
Is YAML faster than JSON?
No. JSON parses faster and more predictably. YAML trades speed for human readability and features like comments and anchors, which is why JSON dominates APIs and YAML dominates config files.
Can I convert JSON to YAML and back?
Yes — they map cleanly because YAML is a superset of JSON. Use the JSON to YAML and YAML to JSON converters; round-tripping preserves the data (comments are JSON-only-lossy, since JSON has none).