YAML Validator

The YAML Validator is a fast, browser-based tool that checks your YAML files for syntax errors, structural problems, and parsing failures. Whether you are working with configuration files, CI/CD pipelines, Kubernetes manifests, or Docker Compose files, valid YAML is critical — a single misplaced indent or rogue tab character can silently break your entire setup. This tool gives you immediate, clear feedback on exactly what is wrong and where.

YAML's indentation-sensitive syntax makes it deceptively easy to introduce errors that are hard to spot with the naked eye. Tools like linters and editors sometimes miss subtle issues such as duplicate keys, improper use of special characters, or mixed tabs and spaces. The YAML Validator parses your input against the YAML 1.2 specification and surfaces every problem with actionable error messages, so you can fix issues before they reach production.

Using the tool is straightforward: paste your YAML content into the input area and the validator will parse it immediately. If your YAML is valid, you will see a success confirmation along with a structured preview of the parsed data, which helps you verify that the document is interpreted exactly as you intended. If errors are found, the tool displays each issue with a line number and a description of the problem, making it easy to pinpoint the exact location of the fault.

Common errors the validator catches include incorrect indentation levels, tabs used instead of spaces, missing colons after keys, improperly quoted strings containing special characters like colons or brackets, and invalid anchor or alias references. Multiline strings using block scalars (| and >) are fully supported, as are complex nested structures, sequences, and mappings.

One important edge case to be aware of: YAML supports multiple documents within a single file separated by ---. The validator handles multi-document YAML streams, but make sure you are intentionally using this format if your file contains multiple --- separators — an accidental separator will split your document and may cause unexpected validation behavior.