Regex Match Checker
Check Which Parts of Your Text a Regex Actually Matches
Need to use Regex Match Checker right now?
A regex that looks correct can still match more (or less) than intended — an unescaped special character, a greedy quantifier grabbing too much. This tool runs your pattern against real sample text and highlights every match live, including individual capture groups, so unexpected behavior is obvious immediately.
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Features
- Runs entirely in your browser
- Privacy-first — your data is never uploaded
- Real-time, instant results
- 100% free, no sign-up required
- Works on desktop, tablet, and mobile
- No installation needed
Who uses this tool?
About Regex Match Checker
Regular expressions (regex) are a compact, powerful pattern language for matching, extracting, and validating text — used everywhere from form validation (checking that an email address or phone number looks right) to search-and-replace in a code editor, log file parsing, and data extraction. They're also notoriously easy to get subtly wrong: a pattern that seems correct can fail to match an edge case, or worse, match something you never intended it to.
A regex tester closes that feedback loop instantly. Instead of writing a pattern into your actual code, running it, and debugging why it didn't match, you type your pattern and a sample test string directly here and see every match highlighted in real time as you adjust either one. This tool uses JavaScript's native RegExp engine — the exact same regex implementation used by every JavaScript and TypeScript codebase, and very close to what's used in most other modern languages — so a pattern that works here will behave identically in your actual application code.
Flags control how the pattern behaves: `g` (global) finds all matches in the string rather than stopping after the first one — this tool always applies it internally so you see every match, regardless of what you type. `i` makes matching case-insensitive. `m` changes how `^` and `$` behave with multi-line text, matching the start/end of each line rather than only the start/end of the whole string. `s` makes `.` match newline characters too, which it doesn't by default. You can combine multiple flags, like `gi` for global, case-insensitive matching.
Matches are highlighted directly within your test string, so you can visually confirm the pattern is capturing exactly the text you expect — no more, no less. If your pattern has a syntax error (an unclosed group, an invalid escape sequence), the tool shows the exact error the RegExp engine reports, the same message you'd see thrown as an exception in your own code.
How it works
- Enter your pattern and flags. Type your regular expression and any flags (i, m, s) you need.
- Paste a test string. Enter the text you want to test your pattern against.
- See matches highlighted live. Every match is highlighted directly in the text, updating as you type.
Examples
Matching phone number patterns
Input
Pattern: \d{3}-\d{4}
Text: Call 555-1234 or 555-5678 for support.Output
2 matches found: 555-1234 and 555-5678