SearchCtrl K
WarpTool
Code & DataText ToolsImage & MediaFont StylesSEO & Web
Back

YAML Validator

Validate YAML syntax and structure, detecting indentation errors and type mismatches.

100% Client-Side Local Execution
Input Data
1 2 3 4
Transformed Result
Valid YAML Syntax
No syntax errors found. The YAML document is well-formed.
Path:JSON
{
"server":{
"host": "localhost",
"port": 8080
},
"debug": true
}

What is YAML Validator?

The YAML validator checks whether a YAML document is syntactically correct, catching the indentation errors, tab-vs-space mistakes, and structural issues that make YAML notoriously easy to break. It's aimed squarely at the DevOps workflows — Kubernetes manifests, GitHub Actions workflows, Docker Compose files — where a single misplaced space causes a deployment to fail.

Technical Execution

The validator parses your document using a YAML 1.1/1.2-compatible parser that enforces YAML's significant-whitespace indentation rules, then reports the line and reason for failure when parsing breaks — commonly inconsistent indentation, a tab character where spaces are required, or an unclosed flow collection.

Zero Data Storage Guarantee

Validation happens entirely in your browser, so YAML config files — which frequently contain secrets, connection strings, or internal service names for Kubernetes and CI pipelines — are never uploaded to a server.

How to Use YAML Validator (Step-by-Step Guide)

  1. Paste the YAML document you suspect has a syntax error
  2. Review the instant valid/invalid status
  3. If invalid, check the reported line number and error description
  4. Fix the indentation or syntax issue (often a tab character or misaligned list item)
  5. Re-validate until the document parses cleanly

Frequently Asked Questions (FAQ)

Q: Why is YAML syntax so easy to get wrong?
A: YAML uses indentation (spaces only, never tabs) to express structure, so a single misaligned space or an accidental tab character can silently change the document's meaning or break parsing entirely.
Q: Is this the same as a YAML linter?
A: Yes, 'YAML lint' and 'YAML validator' both describe checking a document for syntax correctness, which is what this tool does.
Q: Can I validate a Kubernetes manifest with this tool?
A: Yes, Kubernetes YAML files are standard YAML syntax, so the validator checks their structural correctness, though it doesn't validate against the Kubernetes API schema itself.
Q: Does it catch tabs used for indentation?
A: Yes, since YAML spec disallows tabs for indentation, a tab character in an indented block is a common error this validator flags.
Q: Can I validate YAML online for free without limits?
A: Yes, there's no account requirement and no cap on usage.
Q: Does it support multi-document YAML files (separated by ---)?
A: Yes, documents separated by the --- marker, common in Kubernetes manifests, are handled as part of the validation.
Q: What's the difference between this and the YAML formatter?
A: The validator's job is to confirm correctness and point at errors; the formatter assumes valid YAML and reflows its indentation for consistency.
Q: Does it check YAML anchors and aliases (&, *)?
A: Yes, anchor and alias syntax is parsed as part of standard YAML, so malformed anchor references will be flagged as errors.
Report an issue with this tool