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YAML Validator

Validate YAML with a real parser, spot indentation issues, and keep configs private in your browser.

Results

Paste input and validate locally.
Status
Ready when you validate.
Details
Ready when you validate.

How to use this validator

  1. Paste your YAML snippet or config.
  2. Run validate to parse and apply indentation heuristics.
  3. If invalid, fix the reported line (often a missing colon or mixed tabs/spaces) and re-validate.

Rules & checks

Parses YAML with a full parser, then applies indentation/colon heuristics for clearer messaging.

Ignores commented/blank lines and reports the first parse error message when parsing fails.

Best for snippets up to a few hundred KB to keep the browser responsive.

Fully client-side/offline—no YAML leaves your browser.

Inputs explained

  • YAML content

    Paste UTF-8 YAML. Prefer spaces (2–4) over tabs; keep payloads modest for browser speed.

When to use it

  • Pre-flight check for Helm/Kubernetes manifests before committing
  • Validate CMS/exported YAML (Netlify, Astro, Next configs) pasted from docs or chat
  • Sanity-check YAML sent by users in forms or support tickets
  • Prep YAML before converting to JSON or running a JSON Schema check

Common errors

  • Missing colon between key and value
  • Mixed tabs and spaces in the same block
  • Inconsistent indentation levels for child keys
  • Accidental tab characters copied from editors
  • Trailing spaces that break alignment

Limitations

  • Syntax-focused: does not enforce JSON Schema/OpenAPI/custom schemas.
  • Very large YAML files may be slow in the browser; keep under a few hundred KB.
  • Does not fetch remote YAML—paste content directly.
  • Heuristics help with indentation but cannot guarantee full spec conformance for edge cases.

Tips

  • Normalize indentation to 2 or 4 spaces—never tabs.
  • If the error points to a line start, check the prior line for a missing colon or dash.
  • Keep large files small in-browser; chunk or validate sections if performance dips.
  • After syntax passes, run schema checks in CI for stricter validation.

Examples

Valid deployment snippet

  • apiVersion: v1
  • kind: ConfigMap
  • data:
  • LOG_LEVEL: info -> Valid

Valid list with objects

  • services:
  • - name: api
  • port: 8080 -> Valid

Invalid: missing colon

  • name api -> Invalid (expected ':' after key)

Invalid: tabs in indentation

  • name: api -> Invalid (tabs can break YAML parsers; use spaces)

Deep dive

This YAML validator uses a real parser plus indentation heuristics to surface missing colons, mixed tabs/spaces, and malformed blocks before you ship configs.

Run it client-side for privacy, then follow up with schema validation in CI for production-grade guarantees.

FAQs

Is my YAML uploaded or stored?
No. Parsing stays in your browser and clears on refresh.
Do you support tabs?
We flag tabs because they break YAML in many parsers. Convert tabs to spaces before validating.
Does this enforce schemas?
No. This is syntax + indentation heuristics. Run JSON Schema/OpenAPI or policy checks in CI for deeper validation.
How big can my file be?
Keep it to a few hundred KB for a smooth browser experience. Split larger files or validate in CI.
Can I use it offline?
Yes. Once loaded, it runs entirely offline.

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