JSON to YAML Converter
Convert JSON to YAML and YAML to JSON online instantly. Bidirectional converter with syntax highlighting — handles nested objects, arrays, and all YAML scalar types.
About the JSON to YAML Converter
The DevToolHeaven JSON to YAML Converter provides bidirectional conversion between JSON and YAML formats using the battle-tested js-yaml library. Switch between JSON to YAML and YAML to JSON modes with a single click.
YAML is the preferred format for configuration files in modern DevOps tools — Kubernetes manifests, Docker Compose files, GitHub Actions workflows, and Ansible playbooks all use YAML. This tool makes it easy to convert JSON API responses and data structures into YAML configuration format, and to convert YAML configs back to JSON for programmatic processing.
YAML and JSON represent the same underlying data model — strings, numbers, booleans, null, objects, and arrays. YAML is a superset of JSON: all valid JSON is also valid YAML. The key practical differences are that YAML uses indentation instead of brackets, supports inline comments with #, and handles multiline strings more elegantly.
The Flow Level setting controls how nested structures appear. At -1 (default), everything uses readable block style with one property per line. At 0, the entire document is written on a single line in flow style. Levels between these apply flow style only to structures nested beyond that depth — useful for keeping top-level structure readable while compressing deeply nested leaves.
Customize indentation and line width to match your project style guide. The converter uses the js-yaml library, which produces canonical and unambiguous YAML that passes validation in all major YAML parsers. The output is compatible with Kubernetes, Docker Compose, GitHub Actions, Ansible, and any other YAML 1.2 parser.
All conversion is done client-side — your data never leaves your browser. The tool works offline after the page has loaded, making it safe for converting configuration files that contain API keys, credentials, or other sensitive values.
Frequently Asked Questions
YAML (YAML Ain't Markup Language) is a human-friendly data serialization format. It uses indentation instead of brackets and braces, making it more readable than JSON. YAML is widely used for configuration files in tools like Docker, Kubernetes, GitHub Actions, and Ansible.
Use YAML for configuration files that humans read and edit frequently — it is more readable and supports comments. Use JSON for API responses and data interchange between programs — it is more universally supported and faster to parse. YAML is a superset of JSON, so all valid JSON is also valid YAML.
Flow level controls how deeply nested structures are rendered inline (flow style) versus block style. A flow level of -1 (default) uses block style for everything. A flow level of 0 puts the entire document inline. Higher numbers use inline style only for structures nested deeper than that level.
Yes — YAML supports single-line comments starting with #. However, since JSON does not support comments, any YAML comments are lost when converting YAML to JSON. When converting JSON to YAML, no comments are added since the original JSON has none.
YAML has multiple ways to represent the same data — block style versus flow style, quoted versus unquoted strings. The js-yaml library used by this tool produces canonical, unambiguous YAML that is always valid. The format may differ from hand-written YAML but is semantically identical.
Yes. This tool produces standard YAML compatible with Kubernetes manifests, Docker Compose files, GitHub Actions workflows, and any other YAML-based configuration system. Convert your JSON configuration to YAML format and paste it directly into your config files.
js-yaml adds quotes around strings that could be misinterpreted as other types — for example the string "true" gets quoted to distinguish it from the boolean true, and "1.0" gets quoted to distinguish it from the number 1.0. Strings with colons or other YAML-special characters are also quoted to avoid parse errors. The quotes are semantically correct.
Yes. YAML supports anchors and aliases (&anchor, *alias) for reusing values, multi-document streams (---), comments, non-string keys, and binary data. This converter handles the standard YAML subset that maps cleanly to JSON. When converting YAML to JSON, anchors and aliases are resolved, comments are discarded, and the result is valid JSON.
Structure your deployment as a JSON object with the required Kubernetes fields (apiVersion, kind, metadata, spec), then paste it here and convert to YAML. The output is ready to use with kubectl apply -f. Most Kubernetes documentation shows YAML examples, but the API accepts both formats — use this tool to convert between them as needed.
Paste your package.json content here and convert. The output is valid YAML representing the same data. Note that tools like npm and yarn specifically require package.json in JSON format — YAML is not accepted. The converted YAML is useful for documentation, configuration management tools, or working with tools that prefer YAML input.
Anchors (&name) mark a value for reuse, and aliases (*name) reference it elsewhere in the document — eliminating repetition. For example: defaults: &defaults timeout: 30 and then service1: <<: *defaults port: 8080. When converting YAML with anchors to JSON, the aliases are fully resolved and the repeated values appear in full in the JSON output.
YAML was designed to be more human-readable than JSON or XML. Indentation (like Python) makes the hierarchical structure visually clear without requiring brackets, braces, or commas. This makes YAML ideal for configuration files that humans read and edit frequently, but it also means whitespace errors (wrong indentation) can cause parse failures — a common gotcha when writing YAML by hand.