YAML Validator Online

Validate YAML syntax and find indentation errors — precise error reporting for config files

What Is YAML Validation?

YAML validation checks whether a YAML document conforms to the YAML specification (currently YAML 1.2) and reports syntax errors with their exact locations. YAML's whitespace-sensitive format means that indentation errors, tab characters (not allowed), inconsistent spacing, duplicate keys, and incorrect data type formatting all cause parsing failures. A validator catches these issues and provides actionable error messages.

YAML validation is critical for DevOps and infrastructure workflows because Kubernetes manifests, Docker Compose files, GitHub Actions workflows, Ansible playbooks, Helm charts, and CI/CD configurations all use YAML. A single indentation error in a Kubernetes deployment can prevent pods from starting. Validating YAML before applying it to production infrastructure prevents downtime, failed deployments, and cascading configuration errors that are difficult to debug in live systems.

How to Validate YAML Online

1. Paste your YAML content into the editor — validation begins automatically
2. Valid YAML shows a green checkmark; errors show red markers at the exact problem location
3. Read the error description: indentation issues, type problems, or syntax errors
4. Fix the reported issues — the most common are inconsistent indentation and tab characters
5. Validate before deploying: catch errors here instead of in production

Why Use PinusX YAML Validator?

PinusX validates your YAML with 100% client-side processing in your browser. Your Kubernetes manifests, Docker Compose files, CI/CD configurations, and infrastructure-as-code files never leave your device. These files often contain sensitive information: image registry credentials, environment variables, secret references, and internal service endpoints. In November 2025, jsonformatter.org leaked over 80,000 user credentials from server-side processing. PinusX prevents this by running the YAML parser entirely in your browser tab. Validate your production configs safely and privately.

Frequently Asked Questions

Why does YAML not allow tabs?

The YAML specification explicitly forbids tab characters for indentation — only spaces are allowed. This prevents ambiguity since different editors display tabs at different widths (2, 4, or 8 spaces). If your YAML contains tabs, the validator will flag them with their exact position. Configure your editor to use spaces for YAML files.

What indentation should YAML use?

Two spaces per level is the most common convention for YAML in the DevOps ecosystem (Kubernetes, Docker, Ansible all use 2-space indentation in their documentation). Some projects use 4 spaces. The key requirement is consistency — mixing indentation levels within the same file causes parsing errors.

Does it validate Kubernetes-specific YAML?

Our validator checks YAML syntax per the YAML 1.2 specification. It does not validate Kubernetes-specific schema (like required fields for a Deployment). For Kubernetes schema validation, use kubectl --dry-run or kubeval after confirming the YAML is syntactically valid with our tool.

How does it handle multi-document YAML?

YAML files can contain multiple documents separated by '---'. Our validator checks each document independently and reports errors with the document number and line number. This is important for Kubernetes manifests that combine multiple resources in a single file.

What about YAML anchors and aliases?

The validator correctly handles YAML anchors (&name), aliases (*name), and merge keys (<<:). It verifies that aliases reference existing anchors and that the resulting expanded structure is valid. Missing anchor references are reported as errors with the alias location.

Your data never leaves your browser. 100% client-side processing.