The share link contains your schema — share it only where you'd share the schema itself.
About the YAML validator
YAML is a human-friendly data format widely used for configuration — Docker Compose files, Kubernetes manifests, CI pipelines and application settings. Because YAML relies on indentation rather than brackets to express structure, small whitespace mistakes can quietly break a config. This tool validates YAML syntax and structure: it confirms that your document parses correctly and is well-formed.
The most common failures it catches are indentation problems. YAML structure must be expressed with spaces, never tabs, and sibling keys must be indented consistently; a stray tab or a misaligned block is the usual culprit behind a parse error. The validator reports the line where parsing failed, so you can click straight to it. Duplicate keys within the same mapping are also flagged as errors rather than being silently merged — a duplicate key is nearly always a mistake.
Note that this checks YAML as YAML — its syntax and structure — not your YAML against a particular configuration schema. If your file is really an OpenAPI specification, validate it with the OpenAPI Validator instead, which checks it against the OpenAPI meta-schema. As with every tool here, validation runs entirely in your browser and nothing is uploaded.
YAML validation FAQ
YAML 1.1 vs 1.2 — which is supported?
Both. The validator parses YAML 1.2, which is the current specification and a strict superset of JSON, while remaining tolerant of the YAML 1.1 conventions found in many existing config files. In practice, the documents people write for tools like Docker Compose, Kubernetes and CI pipelines validate cleanly.
Why is my indentation invalid?
YAML uses indentation to express structure, and it must be made of spaces, not tabs. The most common causes of an indentation error are a stray tab character, inconsistent indent widths between sibling keys, or a nested block that isn't indented further than its parent. The error message points to the line where parsing failed.
Does it check my YAML against a schema?
No. This page validates YAML syntax and structure — that the document parses and is well-formed. It does not check your YAML against a particular config schema. If your YAML is actually an OpenAPI document, use the OpenAPI Validator, which checks it against the OpenAPI meta-schema.
Are duplicate keys flagged?
Yes. Duplicate keys in the same mapping are reported as an error rather than silently overwriting one another, since a duplicate key is almost always a mistake and a frequent source of confusing config bugs.