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Regex Tester

Test regular expressions against text with real-time matching and highlighting.

Regular Expression
Quick patterns
Matches

Overview

Test regular expressions and inspect matches quickly.

Best for

  • Validate formats like emails or IDs.
  • Extract patterns from logs.
  • Extract IDs from logs or filenames.

Step-by-step

  1. Enter your regex pattern and flags.
  2. Paste the test text.
  3. Review matches and groups.

Examples

Example 1
Input
Pattern: \b\d{4}-\d{2}-\d{2}\b | Text: 2025-03-01
Output
Matches: 2025-03-01
Finds ISO date strings.
Example 2
Input
Pattern: ([A-Za-z]+)@([A-Za-z.]+) | Text: info@example.com
Output
Groups: info / example.com
Captures local and domain parts.
Example 3
Input
Pattern: \b\d{3}-\d{2}\b | Text: 123-45, 678-90
Output
Matches: 123-45, 678-90
Global matching finds all codes.

Common mistakes

  • Greedy patterns may match too much.
  • Regex features differ across engines.
  • Missing the global flag returns only the first match.

Pro tips

  • Start with a small test string.
  • Use non-greedy quantifiers when needed.

FAQ

Why are there no matches?
Check flags, escaping, and line breaks.
Does this upload my data?
No. Everything runs locally in your browser.
Can I use it offline?
Yes. After the page loads, most tools work offline. Some assets (like fonts) may need a connection.

Data & privacy

All processing happens locally in your browser. No data is uploaded or stored.

Why this page is useful in real work

The widget gives you a fast result. This review section explains where that result is genuinely useful and where a second check still matters before you act on it.

Real workflow fit

Developers prototyping extraction logic, validating text shapes, and debugging content cleanup rules before implementation.

What this output still does not decide

A regex that matches once can still be too broad, too slow, or dangerous in production under larger inputs.

Review before you share or ship
  • Flag behavior for multiline, global, case-sensitive, and unicode matching.
  • Negative examples so false positives are visible before rollout.
  • Performance risk from catastrophic backtracking or nested repetition.
A practical workflow that keeps this page useful
  1. Begin with a tiny sample that demonstrates the shape you want to match.
  2. Add representative positive and negative cases before celebrating a hit.
  3. Review capture groups and boundary conditions after each revision.
  4. Move the final pattern into automated tests before shipping it.
Best next step

The fastest way to trust a regex is to pair this page with a real test suite, not to keep tweaking it in isolation.