RegEx Tester

What RegEx Tester is

RegEx Tester is a free, open-source web tool for checking regular-expression patterns against text. Enter a pattern and test text in separate fields, then review the output in the Result area. It supports .NET, Node.js, Python, and Java regex flavors, which lets users work with patterns for those environments in one browser-based tester.

The interface provides options including IgnoreCase, Multiline, ExplicitCapture, Compiled, Singleline, IgnorePatternWhitespace, RightToLeft, ECMAScript, CultureInvariant, and NonBacktracking. ShowCaptures displays capture information. For replacement work, the page includes Replace and To inputs.

RegEx Tester is available online through its GitHub Pages site, and the maker links to source code hosted by the RegExTester GitHub organization. The maker reports that the tool served 1.5k users with 2k test sessions in 2021. Its focused interface is suited to trying patterns, viewing results, checking capture output, and preparing replacement text without installing a desktop application.

Who it suits

RegEx Tester suits developers and others who need to check regular-expression behavior against sample text in a browser. It is useful for users working with .NET, Node.js, Python, or Java regex flavors, especially when captures or replacement text are part of the task.

Getting started

1. Open the RegEx Tester GitHub Pages website.
2. Enter a regular-expression pattern and test text.
3. Choose relevant regex options and flavor.
4. Review the Result area and use ShowCaptures or the Replace and To fields as needed.

Verdict

Choose RegEx Tester when you want a free browser tool to try patterns, inspect results, and work with captures or replacements. Its support for four regex flavors makes it useful for checking behavior across those environments. Look elsewhere if you need a platform beyond the web.