JSON to YAML & YAML to JSON Converter — Both Directions (Free)
Convert between JSON and YAML in either direction. Preserves types, comments where possible, indentation control. Free.
About JSON to YAML Converter
A JSON to YAML and YAML to JSON converter translates between the two most common human-readable structured-data formats — JSON (concise, brace-delimited, programmer-friendly) and YAML (indentation-based, more human-readable, used heavily in configuration). The ZTools JSON/YAML Converter handles either direction, validates input before converting, preserves types (numbers stay numbers, booleans stay booleans), supports YAML-specific features (anchors, aliases, multi-line strings) when converting from JSON, and lets you pick indentation (2 or 4 spaces) for consistent output.
Use cases
- Switching config formats between projects. GitHub Actions uses YAML; older CI tools use JSON. Convert your existing config when migrating between systems.
- Reading API responses in YAML. JSON API responses are dense and hard to scan. Convert to YAML for code reviews and incident postmortems — easier to read.
- Authoring Kubernetes configs in JSON, deploying as YAML. JSON has better tooling support for generation; YAML is the kubectl-friendly format. Author in JSON, convert at deploy time.
- OpenAPI / Swagger spec translation. OpenAPI specs work in both formats. Some teams prefer YAML for authoring; others prefer JSON for diffs. Convert to whichever the team uses.
How it works
- Pick the direction. JSON → YAML or YAML → JSON. The same input field accepts either; auto-detect determines which.
- Paste your data. Validates first. Malformed JSON or YAML produces an error with line and column info before conversion.
- Configure output format. YAML output: indentation (2 or 4 spaces), flow style (compact inline) vs block style (one item per line), explicit document marker (---). JSON output: pretty-printed (default 2-space) or minified.
- Read the converted output. Side-by-side preview shows source vs converted. One-click copy or download.
Examples
Input: JSON: {"name":"Alice","tags":["admin","user"]}
Output: YAML:
name: Alice
tags:
- admin
- user
Input: YAML: a: 1
b: 2
Output: JSON: {"a":1,"b":2}
Input: YAML with anchor: defaults: &d
retries: 3
prod: *d
Output: JSON: {"defaults":{"retries":3},"prod":{"retries":3}}
YAML anchors are expanded — JSON has no equivalent.
Frequently asked questions
When should I use JSON vs YAML?
JSON: programmatic data, API requests/responses, machine-to-machine. Pros: simpler spec, faster parsing, no indentation gotchas. YAML: human-authored config files (Kubernetes, CI, OpenAPI). Pros: readable, supports comments, less punctuation noise.
Can YAML express things JSON can't?
Yes: comments, anchors and aliases (DRY references), multi-line strings with literal/folded operators, tagged types (e.g., !!int "123"). Converting YAML → JSON loses these — anchors are expanded; comments are dropped.
What about JSON things YAML can't do?
YAML 1.2 is a superset of JSON in practice — anything valid in JSON is valid YAML. Converting JSON → YAML is always safe; the reverse may lose YAML-specific features.
How are dates handled?
JSON has no date type — dates are typically ISO strings. YAML 1.2 supports timestamps natively but they're commonly written as strings too. The converter preserves string form by default.
How is duplicate-key handling?
Both formats technically reject duplicate keys, though many parsers accept them silently. The converter validates and warns; if a YAML input has duplicates, the JSON output will have only the last value (overwrite behavior).
Pro tips
- Use JSON for machine-to-machine; YAML for human-edited config.
- YAML's strict-indentation rule means small whitespace mistakes break parsing — validate before conversion.
- When converting YAML to JSON, comments are lost — keep your YAML version if comments are important.
- For consistent output, pick a single style (block vs flow YAML) per project rather than mixing.
Reviewed by Ahsan Mahmood · Last updated 2026-05-05 · Part of ZTools.
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