What is YAML Validation?
YAML (YAML Ain't Markup Language) is a human-readable data format used extensively for configuration files. Docker Compose, Kubernetes, CI/CD pipelines, and countless other tools use YAML. A single indentation error can break everything.
This validator checks your YAML syntax and reports exactly where problems occur. Catch errors before deployment instead of debugging failed configurations.
YAML Syntax Rules
Key YAML requirements:
- Indentation with spaces only (no tabs)
- Consistent indentation at each level
- Colons after keys: key: value
- Lists start with dash: - item
- Strings with special chars need quotes
Common YAML Pitfalls
Mixing tabs and spaces causes invisible errors. Configure your editor to use spaces.
Strings like 'yes', 'no', 'true', 'false' are interpreted as booleans. Quote them if you mean the literal string.
Colons in values (like URLs) need the entire value quoted: url: 'http://example.com:8080'
Frequently Asked Questions
What is YAML validation?
YAML validation checks if your YAML syntax is correct - proper indentation, valid key-value pairs, correct list formatting, and properly quoted strings where needed.
What are common YAML errors?
Most YAML errors come from: inconsistent indentation, mixing tabs and spaces, missing colons after keys, unquoted strings with special characters, and incorrect list syntax.
Does YAML require quotes around strings?
Usually no, but strings containing special characters (: # [ ] { } , & * ! | > ' ") or starting with special values (true, false, null, numbers) should be quoted to avoid parsing issues.
Tabs or spaces in YAML?
YAML requires spaces for indentation - tabs are not allowed. Use consistent spacing (usually 2 spaces per level). This is a common source of validation errors.