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YAML Validator
Syntax & Structure ValidatorReady
Paste or type data below, then click Validate Syntax (⌘↵) to check compliance.
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YAML Validator & Syntax Checker

Validate YAML syntax online with precise line error diagnostics. Check YAML indentation rules and detect configuration mistakes in your browser.

Line/column error detection
YAML 1.2 check
Multi-doc support (---)
Gutter highlights
Step-by-Step Guide

How to Use YAML Validator Online

Follow these quick steps to process your data online directly in your browser with zero latency and 100% privacy.

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Step 1Parses YAML syntax against YAML 1.2 grammar.
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Step 2Reports exact line and column positions for syntax violations.
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Step 3Calculates key count and nesting depth.
Demonstration

Example Input & Output

Validates YAML syntax, checking mapping alignments, sequence indentation, and literal values.

YAML Code
name: web-service
replicas: 3
image: nginx:latest
env:
  - name: NODE_ENV
    value: production
  - name: PORT
    value: "3000"
Expected Output
✓ Valid YAML (YAML 1.2 Standard)
Applications

Common Use Cases

Docker Compose Verification

Validate docker-compose.yml files before running container stacks.

Ansible Playbook Checks

Catch indentation and syntax errors in Ansible playbooks.

Guidelines

Specifications & Gotchas

Missing Space After Colon

A colon must be followed by a space (key: value), not key:value.

Unescaped Colons in Values

Strings containing colons must be enclosed in quotes.

Knowledge

Frequently Asked Questions

How do I check if my YAML file is valid?

Paste your YAML document into the validator; any syntax or indentation errors are flagged immediately.

What are the most common YAML syntax errors?

The most frequent errors are using tab characters, inconsistent indentation, and omitting the space after colons.

Does this linter support multi-document YAML?

Yes, documents separated by --- are supported.

Workflow

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