YAML Validator
Paste your YAML in the editor below to validate it.
About the YAML Validator
Check YAML syntax as you type - catch indentation mistakes and stray characters before they break a deploy.
- Paste or type your YAML into the editor.
- The result updates as you type: valid YAML is confirmed, errors show the line and column.
- Fix the reported line and watch the result turn valid.
- Convert valid YAML with YAML to JSON if you need JSON.
- YAML is indentation-sensitive: use spaces, never tabs.
- Quote strings such as
"yes","no"or"08"if they must stay strings. - Great for checking CI pipelines, Kubernetes manifests and Docker Compose files.
Validate YAML Online
Paste YAML and see immediately whether it parses. When it doesn't, the message points to the line and column, so you can fix the file before a pipeline or deployment trips over it.
What the validator catches
- Indentation: items that are not aligned with their siblings, and tabs used for indentation.
- Duplicate keys: the same key defined twice in one mapping.
- Unclosed quotes and brackets: strings,
[ ]lists and{ }maps that are never closed. - Malformed structure: a missing space after a colon, or a list item where a key was expected.
Files worth checking
- GitHub Actions, GitLab CI and other pipeline definitions
- Kubernetes manifests and Helm values files
- Docker Compose files
- Ansible playbooks and application config
YAML Validator FAQ
Does it check my Kubernetes or GitHub Actions fields?
No. It checks YAML syntax only - whether the file parses. It does not know which keys a particular tool expects, so a misspelled field name still counts as valid YAML.
Why is my file with several --- documents reported as invalid?
The validator expects a single YAML document. Check each document on its own by pasting them one at a time.
Why can't I use tabs?
The YAML specification forbids tabs for indentation, because their width is ambiguous. Use spaces - two per level is the common convention.
Is my data uploaded to a server?
No. Validation runs entirely in your browser.