Free JSON to YAML Converter Online

• Kubernetes manifests and Helm values
• GitHub Actions and GitLab CI pipelines
• Docker Compose files
• Ansible playbooks and inventories
• Application config (Django, Rails, Spring)
• OpenAPI / Swagger API specifications
• Any file humans frequently read and edit

• REST API request and response bodies
• Browser localStorage and sessionStorage
• package.json, tsconfig.json
• Database JSON/JSONB columns
• Machine-to-machine data exchange
• WebSocket and SSE message payloads
• Any data parsed programmatically at high volume

# Plain string (no quotes needed)
name: Alice

# Quoted string (required when value contains : or #)
message: "Hello: world"

# Literal block scalar — preserves newlines
script: |
  echo "Starting deploy"
  npm install
  npm run build

# Folded block scalar — folds newlines into spaces
description: >
  This is a long description
  that spans multiple lines
  but will be one paragraph.

Single-quoted strings use '' to escape a literal apostrophe. Double-quoted strings support \n, \t, \\ escapes just like JSON.

# Block sequence
fruits:
  - apple
  - banana
  - cherry

# Flow sequence (JSON-style, valid YAML)
colors: [red, green, blue]

# Sequence of objects
users:
  - name: Alice
    role: admin
  - name: Bob
    role: viewer

Each - item is one array element. Objects inside an array are indented further. Flow sequences use JSON bracket syntax and are valid in YAML.

# Block mapping
server:
  host: localhost
  port: 8080
  tls: true

# Flow mapping (JSON-style)
point: {x: 10, y: 20}

# Nested mappings
app:
  database:
    host: db.example.com
    port: 5432

Indentation defines nesting. Two spaces is the standard. Tabs cause parse errors — always use spaces.

# Define an anchor
defaults: &defaults
  replicas: 3
  env: production
  timeout: 30

# Merge with <<: *alias
web:
  <<: *defaults
  port: 80

api:
  <<: *defaults
  port: 3000
  replicas: 5  # override the anchored value

Anchors (&name) mark a node, aliases (*name) reuse it. The merge key (<<) copies all key-value pairs from the aliased mapping — think of it as YAML's object spread. Aliases are resolved to their values when converting to JSON.

YAML forbids tab characters for indentation. Use spaces only. Configure your editor to insert spaces when you press Tab in .yaml files.

The strings yes, no, true, false, on, off are parsed as booleans. Quote them: country: "NO". Norway's country code has caused real YAML bugs.

YAML parsers may accept duplicate keys but behavior varies — some take the last value, others the first. Use unique keys or use an anchor/alias.

A key-value pair requires a space after the colon: key: value. Without the space, the entire string is treated as a plain scalar.

All sibling keys at the same level must have the same indentation. Mixing 2-space and 3-space indent siblings causes parse errors.

import yaml, json

# JSON → YAML
with open('data.json') as f:
    data = json.load(f)
yaml_str = yaml.dump(data, default_flow_style=False, sort_keys=False)

# YAML → JSON
with open('config.yaml') as f:
    data = yaml.safe_load(f)  # use safe_load, not load!
json_str = json.dumps(data, indent=2)

Always use yaml.safe_load() instead of yaml.load() to prevent arbitrary code execution via malicious YAML files (a known security vulnerability in PyYAML).

const yaml = require('js-yaml');
const fs = require('fs');

// JSON → YAML
const data = JSON.parse(fs.readFileSync('data.json', 'utf8'));
const yamlStr = yaml.dump(data);

// YAML → JSON
const yamlContent = fs.readFileSync('config.yaml', 'utf8');
const parsed = yaml.load(yamlContent);
const jsonStr = JSON.stringify(parsed, null, 2);

js-yaml is the most popular YAML library in the Node.js ecosystem. Install with: npm install js-yaml. It also provides a CLI: js-yaml input.yaml > output.json

package main

import (
    "encoding/json"
    "gopkg.in/yaml.v3"
)

// YAML → JSON via intermediate struct
var data interface{}
yaml.Unmarshal(yamlBytes, &data)
jsonBytes, _ := json.MarshalIndent(data, "", "  ")

// JSON → YAML via intermediate struct
var obj interface{}
json.Unmarshal(jsonBytes, &obj)
yamlBytes, _ := yaml.Marshal(obj)

Go's encoding/json and yaml.v3 both work with interface{} as an intermediate. Note that yaml.v3 uses map[string]interface{} for objects, compatible with encoding/json.

Workflow files live in .github/workflows/. Each file defines triggers (on: push, pull_request), jobs with runs-on environments, and steps that either run shell commands or call reusable actions. The uses: keyword references an action; the with: mapping passes inputs.

Every Kubernetes resource — Pod, Deployment, Service, ConfigMap, Ingress — is defined in YAML. The four mandatory fields are apiVersion, kind, metadata, and spec. kubectl apply -f manifest.yaml creates or updates the resource. Helm charts wrap these manifests in templates with {{ .Values.xxx }} placeholders.

docker-compose.yml defines multi-container applications: service names, image references, port mappings, volume mounts, environment variables, and dependencies between services. The depends_on key controls startup order, while networks and volumes are declared at the top level and referenced by services.

API specifications in YAML describe endpoints (paths:), request parameters, request bodies, and response schemas. YAML's multi-line strings and anchors make OpenAPI specs more readable than JSON equivalents — anchors eliminate duplication of shared schemas across multiple endpoints.