YAML Validator
Validate common YAML structures, catch syntax and indentation problems, and preview the parsed data locally in your browser.
Paste YAML
Supports the common mappings, sequences, scalars and block text used in configuration files. Complex YAML tags and anchors are intentionally outside this lightweight validator.
Validation result
What does this YAML validator check?
It checks indentation and parses common YAML mappings, lists, quoted and unquoted values, booleans, numbers, null values, inline arrays and objects, and basic block text. If parsing succeeds, the equivalent data structure is shown as formatted JSON.
Common YAML problems
Tabs in indentation, missing colons, inconsistent nesting and duplicate mapping keys are frequent causes of invalid configuration files. The validator reports the first problem it can identify so you can fix it quickly.
Private by design
Your YAML is processed in the browser. KRIYANO does not send the document to a validation API.
How to use this tool effectively
Check YAML for common syntax and indentation problems before using it in configuration files, CI pipelines or application manifests. The validator also previews parsed data so you can confirm that values are structured the way you intended.
Common uses
- Check configuration copied into a CI/CD pipeline or deployment manifest.
- Find indentation errors after manually editing nested YAML.
- Confirm whether lists and mappings parse into the expected structure.
- Review a YAML snippet before converting it to JSON.
Example: indentation matters
service:
name: api
ports:
- 8080Valid YAML with one service mapping and a ports list.
YAML uses indentation to express nesting. Moving the list marker to the wrong indentation level can change the structure or make the document invalid.
Common mistakes to avoid
- Do not use tabs for indentation in YAML; spaces are the safer standard choice.
- Quote values that could be misread as booleans, numbers, dates or special syntax when exact text matters.
- Be careful when copying examples that rely on advanced YAML features not supported by every parser.
Validation happens locally in the browser. Configuration text is not uploaded to KRIYANO.
Frequently asked questions
Why is YAML indentation so important?
Indentation defines parent-child relationships. A different number of leading spaces can move a value into another mapping or list.
Is valid YAML always valid for my application?
No. Syntax validation only confirms that the document can be parsed. Your application may require a particular schema, field name or value type.
Can YAML contain multiple documents?
Yes, YAML supports multiple documents separated by markers such as ---. This lightweight validator focuses on common configuration-style structures, so application-specific behavior should still be checked with the target system.