ValidatorsRegex Tester & Debugger

Regex Tester & Debugger

Build, test, and debug regular expressions interactively. Highlights all matches inline with clickable detail panels showing capture groups, named groups, and position. Auto-explains every token in your pattern (anchors, quantifiers, lookaheads, character classes, and more). Supports replace with group references ($1, $<name>) and extract with custom format templates. Includes a test-case suite to verify full-match, any-match, or no-match expectations. Supports all JavaScript regex flags: g, i, m, s, u.

Pattern

Test Input

Regex Tester & Debugger guide

Build and debug JavaScript regular expressions with live matches, capture-group details, replacement previews, and token explanations. The tester is designed for practical regex work, from quick validation patterns to multi-case debugging.

Key features

Highlight regex matches and inspect capture groups
Explain anchors, groups, character classes, quantifiers, and escapes
Preview replacements and extract matched values
Create test cases for expected full matches, partial matches, or no matches

Common use cases

Debug a validation pattern before adding it to application code
Understand a regex copied from documentation or an existing project
Check replacement output before running it over real text

Frequently asked questions

Which regex flavor does this tester use?

It uses JavaScript regular expressions, including common flags such as g, i, m, s, and u.

Can it explain a regular expression?

Yes. The tool breaks down tokens such as groups, anchors, quantifiers, character classes, and escapes.

Can I test capture groups?

Yes. Matches include capture-group details so you can inspect numbered and named groups.

JSON Validator

Validate JSON syntax instantly with detailed error messages showing exactly where parsing fails. For valid JSON, displays structural statistics including object count, array count, key count, nesting depth, and value type breakdown.

Text Escape / Unescape

Escape and unescape special characters for use in JSON strings, JavaScript source code, HTML, SQL, and regular expressions. Handles newlines, tabs, quotes, backslashes, and Unicode escape sequences.

Case Converter

Convert text between camelCase, PascalCase, snake_case, kebab-case, SCREAMING_SNAKE_CASE, Title Case, and UPPER/lower case. Ideal for renaming variables, formatting identifiers, or transforming text for different coding conventions.

Word Counter

Count words, characters (with and without spaces), sentences, paragraphs, and estimated reading time. Useful for writing articles, social media posts, SEO content with character limits, or academic papers.