How to use: Regex Tester

Regex Tester is a free online Regex Tools tool that live JavaScript regex testing with match groups highlighted instantly in your browser. Paste your data, adjust the options and get the result in real time — no installation, no sign-up, and nothing is ever uploaded to a server.

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Description

Live JavaScript regex testing with match groups highlighted.

  • Regex Tools
  • Because everything is computed client-side, Regex Tester is safe to use with sensitive data such as API keys, tokens or private logs.
Input Regex Tester Output Runs 100% in your browser — your data never leaves your device.
Regex Tester — Input → Output

How to use

Using Regex Tester takes three steps:

  1. Paste your data into the input box (or load the example).
  2. Configure the options to match your target format or scenario.
  3. Copy, download or inspect the output — it updates live as you type.
How to use · Regex Tester 1 Paste your data intothe input box (or loadthe example). 2 Configure the optionsto match your targetformat or scenario. 3 Copy, download orinspect the output —it updates live as youtype.
How to use

Run

Examples

Try email pattern.

Input

[email protected] and [email protected]

Output

<p class="tb-note">2 matches</p><table class="tb-table"><tr><th>#</th><th>Match</th><th>Index</th></tr><tr><td>1</td><td><code>[email protected]</code></td><td>0</td></tr><tr><td>2</td><td><code>[email protected]</code></td><td>23</td></tr></table><pre class="ex-io"><mark>[email protected]</mark> and <mark>[email protected]</mark></pre>

This output was produced by actually running the tool, not written by hand.

Use cases

Common situations where Regex Tester helps:

  • Live JavaScript regex testing with match groups highlighted.

Parameters

This tool has no options — it works on the input alone.

FAQ

What is Regex Tester?

Regex Tester live JavaScript regex testing with match groups highlighted. It runs entirely in your browser, so your data stays private.

Is Regex Tester free to use?

Yes. Regex Tester is free, unlimited and works without registration or installation.

Does my data get uploaded?

No. All processing happens locally in your browser; nothing is sent to any server.

Good to know

  • Everything runs client-side, so extremely large inputs are limited by your browser tab’s memory rather than by a server upload limit.

Related tools

Regex Replace ToolApply regex replacements with $1 capture references.Common Regex LibraryReady-made patterns for email, URL, phone, dates and more.Base64 EncoderEncode text, JSON, URLs or files to Base64, standard or URL-safe.URL EncoderPercent-encode URLs or single query components.Base64 DecoderDecode Base64 (standard or URL-safe) back to text or bytes.SHA-256 Hash GeneratorCompute the SHA-256 digest — the standard for modern integrity checks.

Regex Tester → · Regex Tools →

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