How to use the YAML Validator
1. Paste your YAML content into the editor on the left.
2. Validation happens instantly — a green badge means valid, red means there is a syntax error.
3. If valid, the parsed structure is shown as JSON on the right so you can confirm it was interpreted correctly.
What is it?
YAML is whitespace-sensitive and easy to break accidentally — a misplaced tab, wrong indentation level, or unquoted special character can silently produce unexpected results or throw a parse error. Validating YAML before deploying it to CI/CD pipelines, Kubernetes clusters, or configuration management systems prevents costly errors.
This validator uses the same YAML parser you'd use in production, so a passing result here means your YAML will parse correctly in your application too. The parsed JSON output lets you verify that nested objects and arrays were understood as intended.
Example
name: Alice address: city: NYC
✗ Invalid YAML YAMLException: unexpected character found while parsing indentation at line 3 Fix: Replace tabs with spaces. YAML prohibits tab indentation.
Use 2 spaces for indentation. Most editors have 'Convert Indentation to Spaces' in their settings.
Benefits
Catch indentation errors before kubectl apply fails
YAML parse failures are almost always whitespace problems — the validator flags the exact line before you waste a deployment.
Validate CI/CD pipeline configurations before committing
Confirm your GitHub Actions, GitLab CI, or CircleCI YAML is parseable before pushing a broken pipeline.
Verify Helm chart values and Ansible playbooks
Ensure YAML configuration is parseable before running expensive or destructive operations against infrastructure.
Identify tab vs space mixing with line-level precision
YAML forbids tabs; the validator flags them with the exact line number — the most common YAML error caught before it breaks anything.
Frequently asked questions
Why does YAML fail with tabs?
The YAML specification explicitly prohibits tab characters for indentation — only spaces are allowed. Most text editors can show whitespace characters; switch them to spaces to fix the error.
Do I need to quote strings in YAML?
Most strings don't need quotes. However, you should quote strings that look like other types (e.g., '1.0', 'true', 'null', 'yes') or contain special characters like : # { } [ ].
What is the difference between YAML null and empty string?
In YAML, a key with no value (key:) or explicit null (key: null) parses as null. An empty quoted string (key: '') parses as an empty string ''. They are different values.