Who this helps
- Developers editing configuration files
- Users inspecting YAML data types
Developer Utility
YAML Validator
Paste YAML code to check syntax errors, indentation issues, missing colons, array structure problems, and view the converted JSON result.
YAML Syntax Validation
Quickly check syntax errors in Docker Compose, GitHub Actions, and Kubernetes configuration files.
Error Location Check
Review indentation, colon, and quotation issues through parsing error messages.
JSON Conversion Support
Convert valid YAML into JSON to inspect the structure more clearly.
YAML Input
Paste the YAML code you want to validate below.
Syntax Validation
Parse the entered YAML in the browser to check syntax and structural errors.
Structure Check
When validation succeeds, the JSON conversion result is shown together so you can inspect objects and arrays.
Validation Result
Check the YAML syntax status, error messages, and JSON conversion result.
Enter YAML code and click the Validate YAML button.
YAML Use Cases
YAML is often used in configuration files, where indentation and structure are important.
Docker Compose
YAML syntax is frequently used in configuration files with many hierarchical structures such as services, volumes, and networks.
GitHub Actions
Automation settings such as workflow, jobs, steps, uses, and run are written in YAML.
Kubernetes
YAML format is widely used for resource definition files such as Deployment, Service, and ConfigMap.
Separate YAML syntax from application configuration rules
Parse YAML, inspect error locations and optionally display JSON and key counts. Syntax success does not validate Docker Compose, Kubernetes or CI-specific settings.
When to use this tool
- Find indentation errors.
- Compare parsed booleans, numbers, strings and arrays.
From input to a checked result
- 1
Remove secrets and prepare one YAML document.
- 2
Paste up to 200,000 characters.
- 3
Enable the JSON and metadata options you need.
- 4
Validate and inspect error line/column or the parsed output.
- 5
Run the target application's own validation after the syntax check.
A simple mapping
- Input
- name: demo ports: - 8000
- Result
- An object with name and a ports array containing 8000.
Review the resulting types, not just the success badge.
Valid syntax, wrong service key
- Input
- services: web: imag: nginx
- Result
- YAML syntax can pass despite the misspelled image key.
A service-specific schema check must detect the configuration mistake.
How it works
The page loads js-yaml 4.3.0 and applies a 10,000 total merge-key limit. After parsing, it inspects unique object/array nodes with limits of 50,000 nodes and depth 100. JSON conversion is optional.
Limitations
- The parser's schema can interpret types differently from the destination application.
- Multiple-document streams require separate handling.
- Circular aliases can be valid YAML but cannot be represented as JSON.
- Resource limits reduce the supported document size and complexity.
Your data
Input is parsed locally. The parser library is loaded from an external CDN; your YAML text is not sent to that CDN.
References
Related tools
- Docker Compose Generator
Prepare a Django and PostgreSQL starter.
- JavaScript Regex Tester
Capture parts of a date string.
Frequently asked questions
Does a green result validate Compose settings?
No. Use docker compose config for Compose-specific rules.
Why is valid YAML not shown as JSON?
A circular alias structure cannot be serialized to ordinary JSON.
Why does a parser error appear in English?
Library diagnostics retain their original wording; surrounding labels and instructions follow the selected language.