YAML Validator

What is YAML?

YAML (YAML Ain't Markup Language) is a human-readable data serialisation format commonly used for configuration files, deployment manifests, and data exchange between services. Its indentation-based syntax makes it more readable than JSON or XML for nested structures, though it can be sensitive to whitespace errors.

YAML validation

YAML's reliance on indentation makes it easy to introduce syntax errors that are hard to spot visually. A misaligned key, a stray tab character, or incorrect nesting can break an entire configuration file. This validator parses your YAML and reports errors with line numbers so you can locate and fix problems quickly, before deploying a broken configuration.

YAML and JSON conversion

YAML and JSON are largely interchangeable formats. Every valid JSON document is valid YAML, but YAML supports features JSON does not: comments, anchors, aliases, and multi-line strings. Converting between the two is useful when an API expects JSON but you prefer to author in YAML, or when you need to strip comments from a YAML file for machine consumption. This tool handles both directions losslessly for standard data types.

Common use cases

Kubernetes manifests, Docker Compose files, GitHub Actions workflows, Ansible playbooks, and CI/CD pipeline definitions all use YAML. Validating these files before applying them prevents deployment failures. Converting them to JSON lets you pipe them into tools or APIs that only accept JSON input.

Privacy

This tool runs entirely in your browser using the js-yaml library. No data is sent to any server. Your input stays on your machine.