Regex Tester: guide & how to use

Enter a pattern and flags (g, i, m, s), paste a test string, and see highlighted matches plus capture groups in a table. Runs locally with the JavaScript RegExp engine. This guide is part of our guides library in the Developer tools category—Regex, JWT, cron, hashing, HTML entities, SQL formatting, permissions, HTTP reference, and JSONPath—browser-only.

What this tool does

Regex Tester — Test JavaScript regex with flags and highlight matches. It fits alongside other utilities on AI Tool Hub so you can solve small problems quickly without installing desktop software.

When it helps

Reach for this tool when your work overlaps with topics like: regex, regular expression, pattern, test, javascript. Teams use these utilities for ad hoc checks during development, studying, content drafting, and light business calculations—always double-check critical numbers against your own policies or professionals when stakes are high.

How to use it

1. Open the tool using the button below.
2. Enter or paste your input in the workspace.
3. Review the output and copy or export it for your project.

Common questions

Which regex flavor is used?

JavaScript (ECMAScript) RegExp, as in browsers and Node.

Related tools

Pair this workflow with other utilities on the site:

• JSONPath Tester

  Query JSON with dot and bracket path expressions.
• JSON Formatter

  Format, minify, and validate JSON in the browser.
• Text Diff / Compare

  Compare two texts line by line with highlights.

Privacy

Like most utilities in this category, Regex Tester runs locally in your browser after the page loads—your content is not sent to our servers for processing.