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YAML Formatter & Validator
Paste YAML to check it for errors and format it with consistent indentation. Comments are kept, and errors show the exact line and column.
0 characters
Formatted YAML
When should you use the YAML Formatter?
- Checking a Kubernetes manifest, Docker Compose file or GitHub Actions workflow before applying it
- Fixing indentation errors in a YAML config
- Making messy or inconsistent YAML tidy and readable
How to use the YAML Formatter
- 1
Paste YAML
Paste a file or snippet. Multiple documents separated by --- are supported.
- 2
Check validation
If the YAML is invalid you'll see the line, column and reason.
- 3
Choose formatting
Pick 2 or 4 spaces and single or double quotes.
- 4
Copy or download
Copy the formatted YAML or download it as a .yaml file.
Examples
Inconsistent indentation fixed
Before
kind: Deployment
metadata:
name: web
labels: {app: web}After
kind: Deployment
metadata:
name: web
labels: { app: web }Common errors and how to fix them
bad indentation of a mapping entry- A line is indented by a different amount than its siblings. YAML uses spaces only — check for a tab or an extra space.
Values like yes, no or on changed meaning- Some YAML parsers read yes/no/on/off as booleans. Quote them ("yes") if you mean the text.
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YAML Formatter FAQ
Yes. Formatting uses Prettier's YAML formatter, which keeps comments, anchors and document separators.
No — YAML only allows spaces for indentation. Tabs cause an error.
It checks that the YAML is syntactically valid. It doesn't check Kubernetes or Compose-specific fields.
YAML is a superset of JSON designed for humans: indentation instead of braces, comments, and less quoting. Use the YAML to JSON converter to switch between them.
Yes. Files with several documents separated by --- are validated and formatted.
No. Everything runs in your browser, so your YAML never leaves your device.