YAML Validator Pro

The parser tracks line numbers as it processes your YAML. When it encounters invalid syntax — such as a tab character used for indentation, a mismatched mapping key, or an illegal scalar value — it reports the exact line number along with a description of the problem so you can jump straight to the issue.

JSON preview converts your valid YAML to an equivalent JSON structure and displays it side-by-side. This is useful for verifying how YAML anchors and aliases resolve, confirming that nested mappings and sequences parsed correctly, and preparing YAML configs for APIs that expect JSON.

Schema hints flag common YAML patterns that may behave unexpectedly: values like 'yes', 'no', 'on', 'off' that YAML 1.1 parses as booleans, bare numbers that might be read as integers, and keys that look like they should be quoted. These hints help you write YAML that behaves predictably across parsers.

The YAML specification explicitly forbids tabs for indentation because tab width is inconsistent across editors and environments, which would make the structure ambiguous. YAML parsers raise an error if tabs are found at the start of a line. Use 2 or 4 spaces consistently.

Block style uses newlines and indentation for structure (the common multi-line format). Flow style uses inline braces {} and brackets [] similar to JSON. Both are valid YAML. This validator handles both styles and highlights mixed-style issues that can confuse certain parsers.

No. All validation and parsing runs entirely in your browser. Your YAML data — including configuration files, secrets references, and Kubernetes manifests — never leaves your machine.