← All Tools

🧾 YAML Formatter / Validator

Format and lightly validate YAML configuration snippets in your browser with line-specific errors, warnings, and copyable debug summaries.

YAML checks
  • Normalizes indentation, trailing whitespace, booleans, nulls, numbers, simple lists, and key/value spacing.
  • Reports typed line errors for tabs, missing keys, and lines that are not key/value pairs, list items, comments, or document markers.
  • Warns about odd indentation, block scalars, empty list items, and keys with spaces.
  • Produces copyable JSON summaries for API/MCP-safe deterministic formatter coverage.
 Runs in your browser
YAML formatting runs locally in your browser. Shared links only include YAML input when you explicitly opt in.
What this tool does
YAML Formatter formats YAML-like configuration text and reports lightweight validation issues with line-specific errors.
Why it is useful
It helps review configs, frontmatter, CI snippets, Kubernetes fragments, and structured settings before use or documentation.
How it works
The browser normalizes common YAML formatting patterns, checks for obvious structural issues, and reports deterministic errors and warnings.
Best input
Paste YAML or frontmatter that should be easier to scan. Keep advanced anchors, refs, tags, and multiline scalars simple when using browser-only lightweight validation.
Safety tip
Be careful with indentation because YAML meaning depends heavily on whitespace.
Privacy note
YAML formatting happens locally in your browser.
Important limitation
YAML dialects and parsers vary; this lightweight formatter does not replace deployment-specific parsers or Kubernetes validation.
Quick answers
Why does indentation matter?
YAML uses indentation for structure, so spaces can change meaning.
Can it validate Kubernetes YAML?
No. Use Kubernetes-specific validation for cluster resources.
API examples
Call the same deterministic core through Utilito’s compact API router. Send only data you intentionally submit to the server-side endpoint.
Try in API playground →Schema →
Format YAML with curl
curl
curl -X POST https://utilito.dev/api/run \
  -H "Content-Type: application/json" \
  -d '{"tool_id":"yaml-formatter","input":{"input":"name: utilito\nprivate: true","action":"format"}}'
Format YAML from JavaScript
javascript
const res = await fetch('https://utilito.dev/api/run', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    tool_id: 'yaml-formatter',
    input: { input: 'name: utilito\nprivate: true', action: 'format' }
  })
});
const data = await res.json();
console.log(data.result.output || data.result.report);
Format YAML from Python
python
import requests
payload = {
    "tool_id": "yaml-formatter",
    "input": {"input": "name: utilito\nprivate: true", "action": "format"},
}
result = requests.post("https://utilito.dev/api/run", json=payload).json()["result"]
print(result.get("output") or result.get("report"))
Common Use Cases
Clean configuration snippets
Normalize pasted YAML from CI, Docker, Kubernetes, or app configuration files before sharing or debugging.
Catch obvious YAML mistakes
Spot tabs, mixed indentation, missing colons, or malformed list entries before sending configs to another tool.
Prepare YAML for docs
Format small YAML examples consistently for READMEs, runbooks, and internal documentation.
Config Formatter Workbench workflow
Move between JSON, YAML, TOML, XML, config conversion, JSON path inspection, and schema validation while keeping snippets local to the browser.
{}JSON Formatter⚙️TOML Formatter / Validator🧾XML Formatter⚙️Config Format Converter🎯JSON Path Tester✅JSON Schema Validator
View all in Code →