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Validators

Code Validators & Testers

Validate JSON, XML (XSD) and HTML, test XPath and regular expressions, generate Quartz cron expressions and validate credit card numbers.

XML Validator — XSD (XML Schema)

Validates an XML string or file against the specified XSD schema. Well-formedness is checked first, then the document is validated against the XML Schema, reporting fatal errors, errors and warnings.

  • Checks well-formedness with precise line/column errors
  • Validates against an XSD pasted, uploaded or referenced via schemaLocation
  • Reports fatal errors, errors and warnings
  • Copy-paste or file upload
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JSON Validator

Validates a JSON string against RFC 8259 and the JavaScript language specification. Configure the validator to be strict or lenient (single quotes, unquoted names, NaN, leading zeroes).

  • Strict RFC 8259 validation with line and column of the error
  • Lenient mode: unquoted names, single quotes, NaN/Infinity, leading zeroes, comments
  • Highlights the exact error position
  • Copy-paste or file upload
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HTML Validator & Linter

Validates HTML documents for well-formedness and best practices: finds missing or unbalanced tags, unknown elements, duplicate IDs, missing required attributes, obsolete markup and more.

  • Detects unclosed, unbalanced and unknown tags
  • Duplicate IDs, duplicate attributes and missing required attributes
  • Obsolete elements and attributes, accessibility hints
  • Copy-paste or file upload
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XPath Tester / Evaluator

Test your XPath expressions against an XML document. Supports XPath functions (string(), number(), name(), string-length()…), namespaces and returns node-sets, strings, numbers or booleans.

  • Full XPath 1.0 support with functions and axes
  • Namespace aware (prefixes resolved from the document)
  • Shows the XML item type of every result
  • Copy-paste or file upload
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Credit Card Number Generator & Validator

Validate a credit card number with the Luhn algorithm and identify its issuer, or generate fake, Luhn-valid test numbers for Visa, MasterCard, American Express, Discover, JCB, Diners Club, Maestro and more.

  • Luhn (Mod 10) validation with issuer detection
  • Fake test numbers for all major brands
  • List of IIN ranges and lengths by issuer
  • Testing only — these numbers cannot make real payments
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Regular Expression Tester

Test your JavaScript regular expressions against any text and clearly highlight all matches and capture groups. Includes a replace mode and a complete regular expression reference.

  • Highlights every match and capture group
  • Flags: global, case-insensitive, multiline, dot-all, unicode, sticky
  • Replace with $1, $2 back-references
  • Regular expression documentation and common solutions
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Java Regular Expression Tester

Test Java regular expressions (java.util.regex) against any input, highlight all matches, and try replaceFirst / replaceAll with $1, $2 group references.

  • Java Pattern flags: CASE_INSENSITIVE, MULTILINE, DOTALL, COMMENTS, UNICODE_CASE, LITERAL…
  • Supports Java syntax such as \p{Alpha}, \Q…\E, \A, \Z, possessive quantifiers
  • matches(), find(), replaceFirst() and replaceAll() modes
  • Regular expression documentation
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Cron Expression Generator & Explainer — Quartz

Generate a Quartz cron expression with an easy to use interface, convert a cron expression into readable text that explains when it will execute, and visualise the next execution dates.

  • Visual builder for seconds, minutes, hours, day, month and year
  • Human readable description of any Quartz expression
  • Next execution dates
  • Large list of cron expression examples
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