Regex Tester & Explainer
Test regular expressions against any text in your browser. Preview matches, inspect capture groups, and understand what each part of your pattern does without leaving the page.
| Match # | Full Match | Groups | Index |
|---|---|---|---|
| 1 | – | – | – |
How to Use
/pattern/flags style.g, i, m, and s. The flags field should stay in sync through the runtime.What This Tool Does
This Regex Tester & Explainer helps you validate regular expressions against sample text without leaving the page. It is useful for debugging validation rules, matching patterns, and understanding how flags and capture groups affect results.
It is designed for practical testing, not marketing theater. You write a pattern, provide test content, and inspect what matched, where it matched, and what each token appears to mean.
Why Use This Tool
Test Faster
Try patterns against real text without jumping between tabs, docs, and code editors.
Inspect Groups
Useful for patterns where you need to extract IDs, dates, slugs, names, or multiple fields.
Understand Syntax
Helpful when you remember roughly what a token does but want a quick explanation while testing.
Debug Inputs
Good for forms, validation logic, data cleaning rules, and developer tooling workflows.
Common Use Cases
Use it to validate email formats, URLs, phone numbers, slugs, product codes, dates, color values, usernames, line-based text patterns, and simple parsing tasks where capture groups matter.
It also fits educational use when you want to understand why a regex works, fails, or behaves differently after changing flags.
FAQ
What is a capture group?
(\d+). It stores the matched part separately so you can inspect or reuse it later.Why does my regex work here but not in my code?
What do ^ and $ mean?
^ matches the start of a string or line, and $ matches the end. Used together, they help enforce full-string matching.