YAML Validator
Paste YAML or load a file to check that it parses; errors come with the line and column, valid documents are also shown as JSON.
- Runs in your browser
- Free to use
About this tool
Docker Compose, GitHub Actions, Kubernetes manifests, Ansible playbooks: YAML is everywhere and it fails on an invisible tab or one misplaced space. The YAML Validator parses the document in your browser with js-yaml, points at the exact line and column of the first error with a hint about the usual causes, and for valid files shows the number of documents, the root type and the content converted to JSON, which makes the structure obvious.
Related: JSON Validator and JSON Formatter.
How to use it — quick steps
- 01
Enter the yaml
Type or paste the yaml in the field above, for example server:. Use Ctrl + V to paste.
- 02
Press "Validate YAML"
Press "Validate YAML" or Ctrl + Enter. The result appears below in an instant. Results can be copied.
- 03
Read the result
It appears in the dark panel under the form instantly. Every block has [copy] and other actions.
Key features of this tool
Nothing leaves your browser
The processing is plain JavaScript that runs on your device: the text you paste is never uploaded to our servers or to anyone else.
Instant results
Results appear the moment you press the button, even for long inputs, and every block has copy and download actions.
Works everywhere
No installation, no account and no limits: the tool works on desktop and mobile, in any modern browser, as often as you like.
Frequently asked questions
Which YAML version is checked?
YAML 1.2 as implemented by js-yaml, the parser used by most Node.js tools; multiple documents separated by --- are supported.
My file is valid in my app but fails here
Custom tags (!!python/… or application-specific !tags) are not part of the default schema and are reported as errors.
Tabs or spaces?
YAML indentation must use spaces; a tab in the indentation is the most common cause of errors.
Are my files or data uploaded?
No. The tool is plain JavaScript that runs in your browser; the files or data you provide here are never uploaded to our servers.