Code Validator
ValidatorsValidate JSON, XML, YAML, CSV, HTML, CSS, SQL, email, URL, IPv4/IPv6, and credit card numbers online. Pinpoints errors with line and column information.
JSON Input
About Code Validator
The multi-format validator checks JSON, XML, YAML, CSV, HTML, CSS, and SQL for syntax correctness, and validates structured values such as email addresses, URLs, IPv4/IPv6 addresses, and credit card numbers against their respective specifications. Validation errors are highlighted with exact line and column coordinates so you can jump straight to the problem without scanning the entire document.
Features
- ✓Validates JSON, XML, YAML, CSV, HTML, CSS, and SQL syntax
- ✓Validates email addresses against RFC 5322 patterns
- ✓Validates URLs including protocol, host, and path components
- ✓Validates IPv4 and IPv6 addresses including CIDR notation
- ✓Validates credit card numbers using the Luhn algorithm
- ✓Shows detailed error messages with line and column numbers
- ✓Format auto-detection — paste content and the validator picks the right mode
- ✓Real-time validation as you type with debounced processing
- ✓100% client-side — your data never leaves the browser
Common Use Cases
- Spotting malformed JSON in API responses before passing them to downstream code
- Checking whether a large YAML configuration file is syntactically valid before deployment
- Verifying a list of email addresses or URLs scraped from a web page
- Confirming that generated SQL is well-formed before running it against a live database
- Validating IPv6 addresses in network configuration scripts
Frequently Asked Questions
QWhich JSON specification does the validator follow?
The validator follows RFC 8259 (JSON) and highlights common deviations such as trailing commas, single-quoted strings, and unquoted keys.
QCan it validate XML against a schema (XSD)?
The current version validates XML well-formedness. Full XSD schema validation is on the roadmap.
QHow are credit card numbers validated?
Using the Luhn algorithm, which checks the check digit. The tool does not verify card existence, issuer, or expiry — only the number format.
QIs my sensitive data safe?
Yes. All validation runs locally in your browser. No data is sent to a server, logged, or stored.
QWhat does the line/column error info mean for JSON?
The validator parses the document and reports the exact character offset of the first unexpected token, making it easy to pinpoint typos in deeply nested structures.