Regex Tester

When this tool helps

Explore JavaScript pattern matches before using a regex in a web validation or text extraction step. Use representative examples, including strings that should not match.

How to use this tool

Patterns run in a dedicated browser worker with a one-second timeout. The output includes match positions and capture groups, capped at 200 matches. This uses JavaScript regex syntax.

A worked example

Input

Text: Order 42, Order 107
Pattern: Order (\d+)
Flags: g

Expected result

Match 1: Order 42 at index 0; capture group: 42
Match 2: Order 107 at index 10; capture group: 107

Enter the pattern without surrounding slash delimiters. The g flag finds repeated matches. The actual result is displayed as JSON with match positions and capture groups; the summary above explains what to look for.

Edge cases and limitations

• The engine is JavaScript, not Java/Kotlin or every Dart target. Verify the expression again in the runtime where your app will use it.
• A one-second worker timeout protects the page from costly patterns. A timeout means the expression needs simplification, not that it has no matches.
• Output is capped at 200 matches. This is a debugging tool, not an exhaustive extraction pipeline.

Use the result in your app

Keep matching and non-matching fixtures in your application tests. Include an unusually long near-match to expose excessive backtracking. For structured formats such as JSON, use a parser instead.

Keep your workflow private

This utility processes input only in this tab. It does not upload or persist pasted content. Review generated output before using it in a production application.