JSON ↔ YAML Advanced Converter

Bidirectional conversion with multi-document YAML, flow vs block style, and full validation.

Style: Indent: JSON indent:
JSON Input
YAML Output
Paste JSON or YAML above to convert.

How to Use the JSON to YAML Converter

  1. Select a direction — "JSON → YAML" or "YAML → JSON" using the chips above.
  2. Paste your data — paste JSON or YAML into the left input area.
  3. Choose style options — select block or flow style, indent width (2 or 4 spaces), and JSON output indent.
  4. View the result — the converted output appears on the right instantly.
  5. Copy or download — use the buttons above the output panel.

About YAML and JSON

YAML (YAML Ain't Markup Language) and JSON (JavaScript Object Notation) are two of the most widely used structured data formats. JSON is the standard for web APIs, JavaScript configuration, and NoSQL databases. YAML is dominant in DevOps tooling — Kubernetes manifests, GitHub Actions workflows, Docker Compose files, Helm charts, Ansible playbooks, and CI/CD pipeline configs are almost universally written in YAML.

Key Differences

  • Readability — YAML uses significant whitespace and indentation instead of braces and brackets, making it feel more like prose
  • Comments — YAML supports # comments; JSON does not support comments at all
  • Multi-document — a single YAML file can contain multiple documents separated by ---; JSON cannot
  • Anchors and aliases — YAML can define a value once with &anchor and reference it with *alias, avoiding repetition; JSON has no equivalent
  • Data types — both support strings, numbers, booleans, nulls, arrays, and objects. YAML additionally has timestamps, binary, and sets as native types
  • Verbosity — JSON requires all string keys to be double-quoted; YAML usually does not

Block Style vs Flow Style YAML

YAML supports two styles for collections. Block style uses newlines and indentation to represent structure, making it the most readable format for human-edited files. Flow style uses braces { } for objects and brackets [ ] for arrays — it looks exactly like JSON, which is valid because YAML is a strict superset of JSON. Flow style is more compact and is sometimes used for short, simple values inline within a larger block-style document.

Multi-Document YAML

A YAML file can contain multiple independent documents, each separated by a line containing exactly ---. This pattern is ubiquitous in Kubernetes, where a single .yaml file typically defines a Deployment, a Service, and possibly an Ingress or ConfigMap, each as a separate document. When converting multi-document YAML to JSON, this tool wraps each document as an element in a JSON array. When converting a JSON array back to YAML, you can opt for multi-document output with --- separators.

Anchors and Aliases

YAML anchors (&name) let you label a value, and aliases (*name) let you reference it elsewhere in the same file. This avoids repetition in large config files — for example, defining a common environment block once and reusing it across multiple service definitions. JSON has no anchor/alias concept, so this converter resolves all anchors and expands all aliases into their full values when converting to JSON.

Common Use Cases

  • Kubernetes manifests — convert JSON output from kubectl get -o json to YAML for version control
  • GitHub Actions — validate workflow YAML structure by converting to JSON and inspecting the data tree
  • Helm charts — convert chart values.yaml to JSON for programmatic processing
  • Docker Compose — inspect or convert compose files, which use YAML format
  • API development — convert OpenAPI/Swagger specs between YAML and JSON representations

Frequently Asked Questions

YAML (YAML Ain't Markup Language) is a human-readable data serialisation format. It is widely used in configuration files for tools like Docker Compose, Kubernetes, GitHub Actions, Ansible, and many others. YAML is a superset of JSON, meaning all valid JSON is also valid YAML.
A multi-document YAML file contains multiple independent YAML documents separated by "---" (three dashes). This is commonly used in Kubernetes manifests where a single .yaml file defines multiple resources. This converter handles multi-document YAML and converts each document to a JSON array element.
Block style YAML uses indentation to represent structure — keys and values are on separate lines. Flow style YAML uses curly braces and square brackets like JSON. Block style is more readable for complex structures; flow style is more compact. This tool lets you choose which style to emit when converting JSON to YAML.
No. The entire conversion runs in your browser using JavaScript. Your data never leaves your device. There is no server, no upload, no logging, and no data collection.
This converter handles strings, numbers, booleans, nulls, arrays, and nested objects. Multi-document files using "---" separators are supported. YAML anchors and aliases are resolved and expanded. Advanced YAML features like custom tags and binary data are not supported as they have no JSON equivalent.