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Free browser-based tool

JSON to YAML Converter

Convert JSON to YAML or YAML to JSON instantly online — free, private, and without installing anything. Paste your data, click Convert, and copy the result. Everything runs in your browser.

295 characters

100% private. All conversion runs in your browser. Your data is never sent to any server.

How It Works

Step-by-step explanation

Choose a direction

Select JSON → YAML or YAML → JSON using the tab switcher at the top of the converter. A sample document is loaded automatically so you can see an example immediately.

Paste your input

Paste any valid JSON object, array, or scalar into the left panel — or paste a YAML document (with or without the --- document marker). You can also click 'Load sample' to restore the built-in example at any time.

Click Convert

The converter parses your input entirely in the browser using a built-in parser — no libraries, no network requests. JSON is serialised to YAML block-style with correct quoting, indentation, and type preservation. YAML is parsed and serialised to pretty-printed JSON.

Copy and use

The output appears in the right panel. Click Copy to copy it to your clipboard. The character count is shown for both panels so you can verify the conversion looks right before pasting it into your project.

Formula

The math behind it

The same data expressed in both formats:

JSON

{
  "server": {
    "host": "localhost",
    "port": 8080,
    "debug": true
  },
  "database": {
    "name": "myapp",
    "pool": 5
  },
  "tags": ["web", "api"]
}

YAML

server:
  host: localhost
  port: 8080
  debug: true
database:
  name: myapp
  pool: 5
tags:
  - web
  - api

Notice: JSON requires quotes around all string keys and values. YAML omits them for plain scalars, uses indentation instead of braces/brackets, and uses - for list items instead of [].

What is JSON?

JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format derived from JavaScript object syntax, standardised as ECMA-404 and RFC 8259. It represents data as key-value pairs (objects) and ordered lists (arrays), with six primitive types: strings, numbers, booleans (true/false), and null. JSON is the dominant format for REST APIs, web application configuration, and data exchange between services. Its strict syntax — quoted keys, explicit brackets and braces, no comments — makes it easy to parse mechanically but verbose to read and write by hand.

What is YAML?

YAML (YAML Ain't Markup Language) is a human-readable data serialisation language designed to be more readable than JSON and XML while remaining a strict superset of JSON. YAML uses indentation to represent structure, making it significantly easier to read and write by hand. It supports comments (lines starting with #), multi-line strings, anchors and aliases for reuse, and additional scalar types like dates. YAML is the standard format for Docker Compose, Kubernetes manifests, GitHub Actions workflows, Ansible playbooks, and many CI/CD systems precisely because it is readable without a specialised editor.

JSON vs. YAML — key differences

The core difference is readability versus strictness. YAML prioritises human readability: no quotes required for strings, indentation as structure, comments allowed, and a more concise syntax for nested data. JSON prioritises machine readability: unambiguous syntax, no implicit type coercion, no comments, universally supported in every programming language. YAML is technically a superset of JSON — every valid JSON document is also valid YAML — which is why converting JSON to YAML always produces valid output. The reverse (YAML to JSON) requires careful handling of YAML-specific features like anchors and multi-document streams that have no JSON equivalent.

When should you use YAML instead of JSON?

Use YAML for human-authored configuration files: infrastructure definitions (docker-compose.yml, Kubernetes YAML), CI/CD pipelines (GitHub Actions, GitLab CI, CircleCI), application config (Rails database.yml, Symfony config), and Ansible playbooks. YAML's comment support is particularly valuable — you can document why a setting exists, not just what it is. Use JSON for machine-generated data, REST API payloads, localStorage, and any context where the data will be read by code rather than humans. The ability to add comments makes YAML significantly more maintainable for config files with many settings.

Convert YAML to JSON — Python example

If you need to convert YAML to JSON programmatically in Python, the standard approach uses the PyYAML library (pip install pyyaml). The pattern is: import yaml, import json, then data = yaml.safe_load(open('file.yaml')), followed by json.dump(data, indent=2). The yaml.safe_load() function is the correct choice for untrusted input as it prevents arbitrary Python object instantiation. For python yaml to json conversion in scripts, you can chain this into a one-liner: python3 -c "import yaml,json,sys; print(json.dumps(yaml.safe_load(sys.stdin), indent=2))" < input.yaml > output.json. This ToolEka converter performs the equivalent operation entirely in the browser without requiring Python or any installation.

Convert JSON to YAML — Python example

For python json to yaml conversion, PyYAML's yaml.dump() function handles the serialisation. The standard pattern is: import yaml, import json, then data = json.load(open('file.json')), followed by yaml.dump(data, default_flow_style=False, sort_keys=False). The default_flow_style=False parameter forces block-style output (one key per line) which is the readable format most developers expect. sort_keys=False preserves your original key ordering rather than alphabetising. For a shell one-liner to convert JSON to YAML: python3 -c "import yaml,json,sys; print(yaml.dump(json.load(sys.stdin), default_flow_style=False))" < input.json > output.yaml

YAML type handling — what to watch for

YAML's automatic type inference is powerful but can surprise developers migrating from JSON. Bare words like yes, no, on, off, true, false are all parsed as booleans in YAML 1.1 (used by PyYAML and many older parsers). This means a key like enabled: yes is parsed as the boolean true, not the string 'yes'. Numbers without quotes become integers or floats. Strings that look like numbers (e.g. version: 1.0) become floats. Dates like 2024-01-15 become date objects in some parsers. When converting YAML to JSON, this tool preserves these type coercions faithfully — which is the correct behaviour for config processing.

JSON vs. YAML — format comparison table

FeatureJSONYAML
Syntax styleBraces, brackets, commasIndentation, dashes
Comments❌ Not supported✅ Lines starting with #
Quotes for strings✅ RequiredOptional for plain scalars
Multi-line stringsEscape sequences (\n)✅ Literal & folded blocks
Type inferenceExplicit (quoted = string)Implicit (yes → boolean)
File sizeSlightly largerMore compact
Human readabilityModerateHigh
Machine parseabilityExcellentExcellent
Superset of JSON—✅ Valid JSON is valid YAML
Common usesAPIs, localStorage, configsDocker, K8s, CI/CD, Ansible

Where is YAML to JSON conversion used in practice?

Understanding when to convert yaml to json (and back) helps you pick the right tool for each part of your workflow. Here are the most common real-world scenarios:

Kubernetes / Helm

Kubernetes manifests are written in YAML. Debugging tools like kubectl and Helm can output JSON. Converting YAML to JSON lets you use jq for querying and transformation.

GitHub Actions

Workflow files are YAML. When writing custom actions or parsing workflow metadata programmatically, JSON is often easier to work with in code.

Docker Compose

docker-compose.yml is YAML. Some container orchestration tools expect JSON equivalents. Convert YAML to JSON when integrating with such tools.

API Payloads

REST APIs speak JSON. If your config is in YAML, convert json to yaml for storage and editing, then yaml to json when sending API requests.

Ansible Playbooks

Ansible uses YAML for all playbooks and inventories. When feeding data into Python scripts or APIs, converting to JSON gives you full ecosystem compatibility.

AWS CloudFormation / SAM

CloudFormation accepts both JSON and YAML. Developers typically author in YAML for readability, then convert json to yaml for version control and review.

FAQ

Frequently Asked Questions