RegExr
What it is
RegExr is a free web tool for learning, building, and testing regular expressions. It supports JavaScript and PHP/PCRE patterns, with results that update as expressions are typed. Hovering over a match or part of an expression reveals details, while the Explain tool gives a plain-English description. Tests mode lets users assemble cases that a pattern should match or reject. Replace and List can generate custom results, and Details displays capture groups. Learning materials include a cheatsheet, reference, help pages, and examples. Users can search and rate Community Patterns, then save and share expressions. Signing in keeps favorites and patterns in My Patterns. Saving creates a public share link, and a copy shared with the Community cannot be edited or deleted. The project README credits Grant Skinner and gskinner.com as creators, identifies this version as GPL v3 licensed, and directs issue and feature requests to GitHub and regular-expression questions to Stack Overflow. RegExr is available on the web and lists a free plan at no cost.
For and against
For
- Supports JavaScript and PHP/PCRE patterns.
- Live results update as expressions are typed.
- Explain describes expressions in plain English.
- Tests mode checks matching and non-matching cases.
- Includes reference materials and examples.
Against
- A Community-shared copy cannot be edited or deleted.
- Saved expressions create public share links.
The verdict
RegExr combines pattern editing with learning resources, test cases, and result tools in a web interface. Keep the public-link and Community-copy limits in mind when saving or sharing expressions.
Who it suits
RegExr suits people learning regular expressions as well as users building and checking patterns. Its test, explanation, and output tools can help people inspect how an expression behaves.
Plans and prices
RegExr
Online regex learning, building, and testing tool
Read 5 Oct 2026 · regexr.com
On the record
- Account storage
- Signing in lets users persist favorites and patterns, which are shown in My Patterns.regexr.com · read 5 Oct 2026
- Community
- Users can search for and rate Community Patterns.regexr.com · read 5 Oct 2026
- Creator
- The project README says RegExr was created by Grant Skinner and gskinner.com.github.com · read 5 Oct 2026
- Explain
- The Explain tool describes an expression in plain English.regexr.com · read 5 Oct 2026
- Learning resources
- The site includes a cheatsheet, full reference, help, and examples.regexr.com · read 5 Oct 2026
- License
- The project README says this version of RegExr is licensed under GPL v3.github.com · read 5 Oct 2026
- Live results
- Results update in real time as you type.regexr.com · read 5 Oct 2026
- Match details
- Rolling over a match or expression displays details.regexr.com · read 5 Oct 2026
- Purpose
- RegExr is an online tool to learn, build, and test regular expressions.regexr.com · read 5 Oct 2026
- Regex flavors
- RegExr supports JavaScript and PHP/PCRE regular expressions.regexr.com · read 5 Oct 2026
- Save and share
- Users can save and share expressions with others and the Community.regexr.com · read 5 Oct 2026
- Sharing limit
- The site says saving creates a shareable public link and that a shared Community copy cannot be edited or deleted.regexr.com · read 5 Oct 2026
- Support
- The project README directs users to GitHub for issues and feature requests and Stack Overflow for regular-expression questions.github.com · read 5 Oct 2026
- Tests
- Tests mode lets users build a suite of tests that an expression should or should not match.regexr.com · read 5 Oct 2026
- Tools
- The Replace and List tools output custom results, and Details lists capture groups.regexr.com · read 5 Oct 2026
