YAML Formatter & Validator
Format, validate, and convert YAML to JSON or vice versa. Paste your YAML below to get started.
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Input
Output (YAML)
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How to Use the YAML Formatter
Our YAML formatter and validator is the essential tool for DevOps engineers, developers, and anyone working with configuration files. Simply paste your YAML into the input area, and the tool instantly validates the syntax and formats it with proper indentation. If there are any errors, you'll see clear error messages with line numbers to help you fix issues quickly.
The Format button beautifies your YAML with consistent indentation (2 or 4 spaces, your choice). Use the To JSON button to convert YAML to JSON format, perfect for API testing or debugging. The To YAML button converts JSON back to YAML, ideal when you need human-readable configuration from API responses.
YAML is whitespace-sensitive — it uses indentation to show data hierarchy, similar to Python. The most common errors are mixing tabs and spaces (YAML requires spaces only) or inconsistent indentation. Our validator catches these immediately, showing you exactly where the problem is so you can fix it fast.
Whether you're writing Kubernetes manifests, Docker Compose files, GitHub Actions workflows, or Ansible playbooks, this tool saves time and prevents deployment errors. Everything runs in your browser — your sensitive configuration data never leaves your computer, making it safe for production files.
The Copy button lets you grab the formatted output with one click. Use the stats display to see the depth of your YAML structure and total number of keys, helping you understand the complexity of your configuration files at a glance.
Frequently Asked Questions
What is YAML and why is it used?
YAML (YAML Ain't Markup Language) is a human-readable data serialization format commonly used for configuration files, Docker Compose, Kubernetes manifests, CI/CD pipelines, and API specifications. It's designed to be more readable than JSON or XML, with minimal syntax and significant whitespace.
How do I validate YAML syntax?
Paste your YAML into the input field and the validator will instantly check for syntax errors. Common issues include incorrect indentation (YAML requires spaces, not tabs), missing colons, or invalid characters. The tool highlights errors with detailed messages to help you fix them quickly.
Can I convert between YAML and JSON?
Yes! Click the 'To JSON' button to convert YAML to JSON format, or paste JSON and click 'To YAML' to convert it back. This is useful when working with APIs that expect JSON but you prefer writing configuration in YAML, or when debugging Kubernetes manifests.
What's the difference between YAML and JSON?
YAML is more human-readable with minimal punctuation and uses indentation for structure. JSON uses brackets and braces explicitly. YAML supports comments and references, while JSON doesn't. YAML is a superset of JSON, meaning all valid JSON is also valid YAML.
Is my YAML data secure when using this tool?
Absolutely. All processing happens entirely in your browser — your data never leaves your computer. This makes it safe for sensitive configuration files, secrets management templates, and production Kubernetes manifests. Always be cautious with actual secrets and credentials.
Why does indentation matter in YAML?
YAML uses indentation to represent data structure and hierarchy, similar to Python. Spaces (not tabs) must be used consistently. Each level of nesting requires the same number of spaces (typically 2 or 4). Incorrect indentation is the most common YAML error and can completely change the meaning of your data.