JSON/YAML Validator & Formatter
Validate, format, and convert JSON and YAML
Paste JSON or YAML to validate, format, or convert between formats. Syntax errors are highlighted with line numbers. All processing happens in your browser — no data is sent to any server.
How JSON/YAML Validation Works
JSON (JavaScript Object Notation) is a lightweight data-interchange format. It uses human-readable text to store and transmit data objects as key-value pairs and arrays. JSON is the standard format for REST APIs and configuration files.
YAML (YAML Ain't Markup Language) is a human-friendly data serialization standard. It uses indentation-based structure instead of braces and brackets, making it more readable. YAML is commonly used for configuration files like docker-compose.yml, Kubernetes manifests, and CI/CD pipelines.
Validation parses the input according to the respective specification. For JSON, the parser checks for proper bracket matching, quoted strings, and correct value types. For YAML, it verifies indentation consistency, colon syntax, and data structure integrity.
Error messages include line numbers to help you quickly locate and fix syntax problems in your data.
Frequently Asked Questions
What is the difference between JSON and YAML?
JSON (JavaScript Object Notation) is a strict data format with braces and quotes. YAML (YAML Ain't Markup Language) is more readable and uses indentation. JSON is the standard for APIs, while YAML is often used for configuration files (docker-compose, Kubernetes).
Are my data stored?
No. All processing happens exclusively in your browser. No data is sent to any server.
Which indentation options are supported?
You can choose between 2 spaces, 4 spaces, and tabs. The default is 2 spaces.
Why does my YAML validation fail?
The most common causes are incorrect indentation (YAML uses spaces, not tabs), missing spaces after colons, or inconsistent indentation depth. The error message shows the exact line.
Can I convert between JSON and YAML?
Yes. The tool supports bidirectional conversion between JSON and YAML. Simply click the corresponding conversion button.