About RegExr
Overview RegExr is an online tool designed to help developers learn, build, and test regular expressions. It supports both JavaScript and PHP/PCRE regex flavors in a single interface. Results update in real time as the user types, and rolling over matches or parts of the expression reveals detailed information. The tool is created by gskinner.com and is free to use without requiring an account. Unlike a library or a command-line regex tester, RegExr offers a visual browser-based environment with syntax highlighting, a full reference guide, and community-shared patterns. Key Benefits Real-time match highlighting updates instantly as you type the expression or test text. Supports both JavaScript and PHP/PCRE regex engines side by side. Includes a comprehensive cheatsheet, full reference, and contextual help accessible from the sidebar. Lets you save expressions and share them with the community via public links. Provides a suite of Tests to validate which strings your expression should or should not match. Offers tools to explore results: Replace & List for custom output, Details for capture groups, and Explain for plain-English breakdowns. How It Works Type a regex pattern into the Expression field and choose JavaScript or PCRE engine via the flags menu. The tool highlights all matches in the Text area as you type. Roll over any match or expression token to see a popup with engine-specific details. Use Cases Web developers testing JS or PHP regex patterns before deploying to production. Data analysts building extraction patterns for log files or structured text. Students learning regular expressions who need visual feedback and a built-in reference. Technical writers verifying that regex examples in documentation match the intended strings. Open-source contributors validating PR changes that include regex logic. Why Choose This Product RegExr is best suited for anyone who needs a free, no-sign-up browser tool to experiment with regular expressions and validate pattern logic before writing code. Its dual engine support and community pattern library reduce the need to switch between multiple tools or command-line utilities. No account is required for basic use, though signing in is needed to save and share patterns permanently.
RegExr Pros & Cons
- Completely free to use, no sign-up required
- Dual engine support (JavaScript & PHP/PCRE)
- Built-in cheatsheet, reference, and contextual help
- Real-time match highlighting and results
- Save and share patterns with the community
Key Features
Real-time highlighting
Matches are colored in real time as you type the expression, and hovering over a match shows detailed engine-specific information.
Dual engine support
Switch between JavaScript and PHP/PCRE regex engines using the flags control to verify cross-engine behavior.
Test suite builder
Build a suite of pass/fail tests that your expression should or should not match, with editable test name, type, and text.
Results exploration tools
Replace and List output custom results, Details shows capture groups, and Explain describes the expression in plain English.
Built-in reference
Sidebar includes a cheatsheet, a full reference with examples, and contextual help for every regex token.
Save and share
Save expressions to create a public link, share them with the Community, and rate or search community patterns.
Community patterns
Search and rate patterns shared by the RegExr community, stored in a searchable public library.
Undo and redo
Use keyboard shortcuts to undo (Ctrl/Cmd+Z) and redo (Ctrl/Cmd+Y) changes in the Expression and Text editors.
RegExr Pricing
View full pricing âPricing extracted from the product website and may change. Check the source for current details.
Frequently asked questions about RegExr
Is RegExr free?
Yes, RegExr is completely free to use. You do not need to sign up or pay to test, edit, and explore regular expressions.
What regex engines does RegExr support?
RegExr supports JavaScript and PHP/PCRE regular expression flavors. You can switch between them using the flags menu.
Do I need an account to save patterns?
You need to sign in to save patterns to My Patterns, add favorites, and share them with the community. Unsaved changes are lost when you leave the page.
What platforms does RegExr support?
RegExr is available on: Web.