EasyConvert / Text & Content

Regex Tester

Test regular expressions with live matching. Free browser-based tool with no signup required.

About Regex Tester

Test regular expressions with live matching.

The tool is designed to process data in the browser unless the interface explicitly states that a network request is required.

How to use this tool

  1. Enter or select the regex, regular expression, text value you want to work with.
  2. Review the available settings, then run the test action.
  3. Review the matches output and use the copy or download action when the tool provides one.

What you can do with Regex Tester

  • Test regex against text
  • Find pattern matches

What this conversion does

Test a JavaScript regular expression against sample text and see every match with its position, using standard JS flags.

Example input

Pattern: \d+, flags: g, text: a1b22

Example output

[1] 1 and [3] 22 — each match listed with its start index

Practical workflow

  1. Type the pattern without surrounding slashes.
  2. Set the flags — keep g to list all matches, add i for case-insensitive, m for multiline anchors, s for dot-all.
  3. Paste the test string and click Test Regex; matches appear one per line as [index] text, or <none>.

Common use cases

  • Check that a validation pattern for emails, phone numbers, or IDs matches the right inputs before shipping it.
  • Find where a pattern matches inside a log line or CSV row while debugging.
  • Learn regex by iterating on a pattern and watching the match list change.

Important notes and limitations

  • Matching runs in your browser with the JavaScript RegExp engine, so results reflect JS semantics — not PCRE, Python, or Java.
  • The g flag is required for listing matches; without it the tool reports Invalid regex, the same message shown for a genuine syntax error.
  • Only the full match and its index are shown; capture groups are not broken out. Patterns with heavy backtracking can freeze the tab.

Continue your workflow

  • Regex Library — start from tested patterns for emails, URLs, dates, and more.
  • Regex Visualizer — see the pattern as a railroad diagram to understand its structure.

Frequently asked questions

Why do I get “Invalid regex” for a pattern that works elsewhere?

Either the flags field is missing g, or the pattern uses syntax JavaScript does not support, such as possessive quantifiers or some look-behind forms in older browsers. Add g and check the JS documentation.

Do I need to include the slashes?

No. Enter only the pattern, for example \d{4}-\d{2}, and put the flags in the separate field.

Can I see capture groups?

This tester lists whole matches with their positions. For group-by-group breakdowns, use the Regex Visualizer to inspect the structure.

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