Online YAML Editor

Free online YAML editor with built-in schema validation for Kubernetes and GitHub Workflows. Includes multi-document support, syntax highlighting, and JSON conversion.

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Features

Multi-document Support

Edit and validate multiple YAML documents in a single file

Schema Validation

Built-in schemas for Kubernetes and GitHub Workflows

Real-time Syntax Validation

Instant error detection and syntax highlighting

Smart Formatting

Auto-indentation and one-click YAML formatting

Format Conversion

Convert between YAML, JSON, and other formats

Frequently Asked Questions

What are YAML data types and how to use them?

YAML supports various data types and structures:

# Scalars (strings, numbers, booleans)
string_plain: Hello World
string_quotes: "Hello World"
number_int: 42
number_float: 3.14159
boolean: true
null_value: null

# Multi-line strings
description: |
  This is a long text
  that spans multiple lines
  with preserved newlines

folded: >
  This is a long text
  that will be folded
  into a single line

# Lists (sequences)
simple_list:
  - item1
  - item2
  - item3

nested_list:
  - name: first
    value: 1
  - name: second
    value: 2

Our editor provides syntax highlighting and validation for all YAML data types.

How do I validate Kubernetes YAML configurations?

Our editor includes built-in Kubernetes schema validation:

# Deployment with resource limits
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80
        resources:
          limits:
            cpu: "1"
            memory: "512Mi"
          requests:
            cpu: "0.5"
            memory: "256Mi"

The editor validates:

  • Resource types and versions
  • Required fields
  • Field types and formats
  • Resource limits and requests
  • Label selectors and references
How to work with multiple YAML documents?

Use document separators (---) to combine related configs:

# ConfigMap for application settings
apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  database_url: "postgresql://db:5432"
  api_key: "development-key"
---
# Service for the application
apiVersion: v1
kind: Service
metadata:
  name: app-service
spec:
  selector:
    app: myapp
  ports:
  - port: 80
---
# Deployment using the ConfigMap
apiVersion: apps/v1
kind: Deployment
metadata:
  name: app-deployment
spec:
  template:
    spec:
      containers:
      - name: app
        envFrom:
        - configMapRef:
            name: app-config

Features:

  • Individual validation per document
  • Cross-document reference checking
  • Document outline navigation
  • Collapse/expand documents
What schema validations are supported?

The editor supports two types of schema validation:

1. Kubernetes Resources

apiVersion: v1
kind: Service
metadata:
  name: my-service
  namespace: default
spec:
  selector:
    app: my-app
  ports:
    - protocol: TCP
      port: 80
      targetPort: 9376

2. GitHub Workflows

name: CI/CD Pipeline
on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - name: Setup Node.js
      uses: actions/setup-node@v2
      with:
        node-version: '14'
    - run: npm ci
    - run: npm test

The editor automatically detects and applies the appropriate schema based on the YAML content. It provides:

  • Resource validation
  • Field type checking
  • Required field validation
  • Action/step validation for workflows
  • Syntax highlighting specific to each schema
How to handle anchors and aliases in YAML?

YAML anchors (&) and aliases (*) help reduce repetition:

# Define common configurations
definitions:
  - &java_container
    image: openjdk:11
    environment: &java_env
      JAVA_OPTS: -Xmx512m
      APP_ENV: prod

# Use the configurations
services:
  api1:
    <<: *java_container    # Merge java_container
    environment:
      <<: *java_env        # Merge java_env
      API_PORT: 8080

  api2:
    <<: *java_container
    environment:
      <<: *java_env
      API_PORT: 8081

Features:

  • Syntax highlighting for anchors/aliases
  • Validation of references
  • Auto-completion for defined anchors
  • Preview of resolved values
How to troubleshoot common YAML errors?

Common YAML issues and solutions:

# 1. Indentation Errors
correct:
  nested:
    key: value    # Consistent 2-space indent

wrong:
   nested:        # ❌ Inconsistent indent
  key: value     # ❌ Wrong level

# 2. Quote Issues
correct_quotes:
  simple: Hello World
  special: "Hello: World"
  multiline: |
    Line 1
    Line 2

# 3. Array Formatting
correct_arrays:
  - item1
  - item2
  - key: value
    other: value

# 4. Boolean Values
correct_booleans:
  - true    # Not True
  - false   # Not False
  - yes     # Alternative
  - no      # Alternative

The editor provides:

  • Real-time error detection
  • Detailed error messages
  • Quick fixes for common issues
  • Format on paste/save options
Where can I learn more about YAML?

Explore these official resources and learning materials:

Official Specifications:

Learning Resources:

DevOps & Configuration:

These resources cover YAML from basic syntax to advanced DevOps configurations!

YAML Syntax Guide

Quick reference for YAML data types, structures, Kubernetes patterns, and common gotchas.

Basic Data Types
string_plain: Hello World\nstring_quoted: "Hello: World"\nnumber_int: 42\nnumber_float: 3.14159\nboolean: true\nnull_value: null

Scalars: strings (plain/quoted), numbers, booleans, null values

Example: name: John Doe
description: |\n  This is a literal block\n  Preserves line breaks\n\nfolded: >\n  This text will be\n  folded into a single line

Multi-line strings: | (literal) preserves newlines, > (folded) joins lines

special_chars: "Use quotes for: colons, brackets, braces"\nno_quotes: Simple values without special characters

Quote strings containing special YAML characters like :, [, ], {, }

Lists & Mappings
simple_list:\n  - item1\n  - item2\n  - item3\n\ninline_list: [item1, item2, item3]

Lists/sequences: block style with dashes or inline with brackets

mapping:\n  key1: value1\n  key2: value2\n\ninline_map: {key1: value1, key2: value2}

Mappings/objects: block style with colons or inline with braces

nested_structure:\n  database:\n    host: localhost\n    port: 5432\n    credentials:\n      username: admin\n      password: secret

Nested mappings and lists with proper indentation

mixed_list:\n  - name: John\n    age: 30\n  - name: Jane\n    age: 25\n  - simple_item

Lists can contain both mappings and simple values

Kubernetes Patterns
apiVersion: apps/v1\nkind: Deployment\nmetadata:\n  name: my-app\n  labels:\n    app: my-app\nspec:\n  replicas: 3\n  selector:\n    matchLabels:\n      app: my-app

Basic Kubernetes resource structure with apiVersion, kind, metadata, and spec

resources:\n  limits:\n    cpu: "1"\n    memory: "512Mi"\n  requests:\n    cpu: "0.5"\n    memory: "256Mi"

Resource limits and requests for containers

env:\n  - name: DATABASE_URL\n    value: "postgresql://localhost:5432"\n  - name: API_KEY\n    valueFrom:\n      secretKeyRef:\n        name: api-secret\n        key: key

Environment variables from values and secrets

Anchors & Aliases
defaults: &default_config\n  timeout: 30\n  retries: 3\n  debug: false\n\nservice1:\n  <<: *default_config\n  name: API Service\n  port: 8080

Anchors (&) define reusable content, aliases (*) reference it, merge (<<) combines

database_config: &db\n  host: localhost\n  port: 5432\n\nproduction:\n  database: *db\n  pool_size: 20\n\ndevelopment:\n  database: *db\n  pool_size: 5

Reuse configuration blocks across different environments

GitHub Actions Patterns
name: CI/CD Pipeline\non:\n  push:\n    branches: [main, develop]\n  pull_request:\n    branches: [main]\n\njobs:\n  test:\n    runs-on: ubuntu-latest

GitHub Actions workflow structure with triggers and jobs

steps:\n  - uses: actions/checkout@v3\n  - name: Setup Node.js\n    uses: actions/setup-node@v3\n    with:\n      node-version: "18"\n      cache: npm\n  - run: npm ci\n  - run: npm test

Action steps with marketplace actions and shell commands

strategy:\n  matrix:\n    node-version: [16, 18, 20]\n    os: [ubuntu-latest, windows-latest]\n  fail-fast: false

Matrix strategy for testing multiple versions and platforms

Docker Compose Patterns
version: "3.8"\nservices:\n  web:\n    build: .\n    ports:\n      - "3000:3000"\n    environment:\n      - NODE_ENV=production\n    depends_on:\n      - database

Docker Compose service definition with build, ports, and dependencies

volumes:\n  postgres_data:\n\nservices:\n  database:\n    image: postgres:13\n    volumes:\n      - postgres_data:/var/lib/postgresql/data\n    environment:\n      POSTGRES_DB: myapp

Named volumes and environment variables for services

Common Gotchas
# Correct indentation\ncorrect:\n  - item1\n  - item2\n\n# Wrong indentation\nwrong:\n - item1  # ❌ Inconsistent\n  - item2

Consistent indentation is crucial - use spaces, not tabs

# Quoted numbers\nversion: "1.2"  # String\nport: 8080      # Number\n\n# Boolean values\nenabled: true   # Not True\ndisabled: false # Not False

Be careful with data types - quote strings that look like numbers

# Multi-document separator\n---\ndocument1: value\n---\ndocument2: value

Use --- to separate multiple YAML documents in one file

Resources

YAML Specification 1.2

Complete YAML specification

YAML Reference Card

Quick syntax reference

Kubernetes YAML Guide

K8s configuration guide

GitHub Actions YAML

CI/CD workflow syntax