Is the Regex Tester private?

The pattern and test text stay in your browser.

What can I use the Regex Tester for?

Parser drafts, Log checks, Validation patterns are common uses. The tool runs in your browser so it is suitable for quick checks and sensitive snippets.

Does HappyFormatter store Regex Tester input?

No. HappyFormatter's utility tools process pasted input in the browser tab and do not store it on a server.

HappyFormatter Local code tools

Browse tools

Private browser utility

Regex Tester

Test JavaScript regular expressions locally in your browser and inspect matches without uploading sample text.

What this tool is good for

Test JavaScript-compatible regular expressions.

Use flags such as g, i, m, s, u, and y.

List match indexes and captured groups.

Runtime

8 families

Python

Application code

Format Python Format with Ruff

PHP

Server script

Format PHP Format with Mago

Go

Application code

Format Go

Dart

Application code

Format Dart

Java

Application code

Format Java

Lua

Script

Format Lua

Shell

New

Script

Format Shell Minify Shell

Rust

Systems code

Format Rust

Systems

5 families

C

Native source

Format C

C++

Native source

Format C++

C#

.NET source

Format C#

Objective-C

Apple source

Format Objective-C Format Objective-C++

Zig

Systems code

Format Zig

Regex Tester

What this tool is good for

Web

HTML

Vue

Svelte

Astro

Angular

Handlebars

Jinja

Twig

CSS

JavaScript

TypeScript

SCSS

Sass

Less

Data

JSON

JSONC

JSON5

XML

YAML

TOML

SQL

GraphQL

Proto

Markdown

MDX

Runtime

Python

PHP

Go

Dart

Java

Lua

Shell

Rust

Systems

C

C++

C#

Objective-C

Zig

Utilities

JSON Tools

Web Encoding Tools

Data Converters

Security Utilities

Color Tools

Markup Tools

Text Utilities

Time Utilities

CSS Utilities