YAML Validator
Validate YAML syntax and structure. Check Kubernetes manifests, Docker Compose files, CI/CD pipelines, and configuration files for parsing errors with detailed error reporting and line numbers.
Recommended Settings
For Kubernetes
- •Validate manifests before kubectl apply
- •Check indentation errors in deployments and services
- •Verify multi-document files have --- separators
For CI/CD Pipelines
- •Validate GitHub Actions workflows before committing
- •Check GitLab CI, CircleCI configs for syntax errors
- •Test pipeline YAML locally to save build time
For Configuration
- •Always use spaces, never tabs for indentation
- •Quote strings with special characters (:, #, -, etc.)
- •Keep nesting depth under 10 levels for readability
Pro Tips
- •YAML requires spaces for indentation - tabs will cause errors
- •Multi-document YAML uses --- as document separator
- •Line numbers in errors help you quickly locate and fix issues
- •All validation happens client-side for complete privacy
Most Popular
Most users validate Kubernetes manifests and CI/CD pipeline configs
When to Use This Tool
Validate Kubernetes YAML manifests (deployments, services, configs) to identify syntax errors before applying to clusters. Catch indentation issues, invalid keys, or structural problems that would cause kubectl apply to fail.
Recommended: DevOps
Check docker-compose.yml files for syntax errors before running containers. Ensure your service definitions, networks, and volumes are properly formatted to prevent docker-compose errors during deployment.
Recommended: Container Management
Validate GitHub Actions, GitLab CI, CircleCI, or other pipeline YAML configs. Identify syntax errors in workflow definitions before committing to prevent pipeline failures and save build time.
Recommended: CI/CD
Validate application configuration YAML files before deployment. Catch parsing errors in Rails configs, Symfony configs, or custom app settings early to prevent runtime crashes and configuration errors.
Recommended: Application Config
Check YAML syntax before converting to JSON, XML, or TOML. Ensure your YAML file is properly formatted to avoid conversion errors and data loss. Identify structural issues that might cause problems during format transformation.
Recommended: Data Migration
Test YAML syntax as you learn the format. Experiment with nested objects, arrays, multi-line strings, and anchors/aliases. Get immediate feedback on syntax errors to understand YAML rules and indentation requirements.
Recommended: Education
How It Works
Paste your YAML content (Kubernetes manifest, Docker Compose, CI/CD config, etc.)
Click 'Validate YAML' to parse and analyze
Tool parses YAML using js-yaml library with full error details
If valid: displays document count, line count, and max nesting depth
If invalid: shows specific error messages with line and column numbers
Check for warnings like tab usage or deep nesting
Copy detailed report for documentation or debugging
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Client-side JavaScript with 'js-yaml' parsing library for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
What does the validator check?
The validator parses your YAML file to check for syntax errors, validates indentation, checks for forbidden tab characters, detects multi-document structures, and calculates nesting depth. It provides line numbers for errors and warnings for best practices.
What are the most common YAML errors?
Common errors include: incorrect indentation (YAML is indentation-sensitive), using tabs instead of spaces, missing colons after keys, unquoted strings with special characters (like :, #, -, etc.), mismatched brackets in flow style, and duplicate keys in the same object.
What's the difference between errors and warnings?
Errors indicate invalid YAML syntax that prevents parsing (red icons). Warnings indicate valid YAML that follows best practices violations like using tabs, deep nesting (>10 levels), or missing document separators in multi-document files (yellow icons).
Can it validate multi-document YAML files?
Yes! The validator supports multi-document YAML files with --- separators. It counts documents, validates each separately, and warns if you're missing document separators when multiple documents are detected. Common in Kubernetes manifests.
Does it check for tabs vs spaces?
Yes! The YAML specification forbids tabs for indentation (only spaces allowed). The validator detects tab characters and issues warnings. This prevents hard-to-debug parsing errors that occur when tabs and spaces are mixed.
What is max nesting depth?
Max nesting depth shows how many levels deep your YAML structure goes. For example, database.connection.pool.max is 3 levels deep. The validator warns if depth exceeds 10 levels, which can indicate overly complex configurations.
Can I validate Kubernetes manifests?
Yes! This tool works with any valid YAML file including Kubernetes deployments, services, config maps, or any other K8s resource. Just paste the YAML content to validate syntax. Note: it only checks YAML syntax, not Kubernetes-specific schema validation.
Is my data safe?
Absolutely! All validation happens entirely in your browser using client-side JavaScript. No data is ever sent to any server, ensuring complete privacy and security for your configuration files including Kubernetes secrets and credentials.