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The Regex Coach
What The Regex Coach is
The Regex Coach is a free graphical application for exploring Perl-compatible regular expressions. It shows whether a pattern matches a target string and updates the display as the pattern or text changes. Users can highlight captured groups or selected parts of a pattern in the target string, and the application can explain a regex in plain English or display its parse tree. A step-through tool follows the matching process, while simulated split and substitution operations help show how Perl handles those transformations. Written in Common Lisp, it uses CL-PPCRE as its regex engine and may suit programmers working with compatible regex toolkits such as PCRE or CL-PPCRE. The current Windows download is version 0.9.2; the maker says the program has not changed since 2008. Linux is no longer maintained, though an unsupported 0.8.5 release is available and also runs on FreeBSD. There is no Mac version planned. The maker provides it as-is without warranty.
Who it suits
It may suit programmers who want a graphical way to examine Perl-compatible regular expressions, especially users of PCRE or CL-PPCRE toolkits. It is less suitable for users who need maintained Linux or Mac software or guaranteed support.
What it does well
- Shows matches as patterns and target text change.
- Highlights captured groups and selected pattern parts.
- Explains patterns and displays parse trees.
- Steps through matching and simulates split and substitution.
What to know first
- No Mac version is available or planned.
- Linux release is unsupported and no longer maintained.
- Maker provides no warranty or promised older-system support.
- Long regular expressions may cause stack overflow.
Limits
The free plan is for private and non-commercial use. Commercial use is free, but redistribution or charging money requires written permission.
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| The Regex Coach | Free for private and non-commercial use · Commercial use is free, but redistribution or charging money requires written permission | Free |
As weitz.de lists them, read 2 Oct 2026. The maker's own page has the final word.
Getting started
- Open the maker’s website.
- Choose the Windows download or the unsupported Linux 0.8.5 release.
- Run the application and experiment with a pattern and target string.
Verdict
The Regex Coach offers interactive inspection and explanation for Perl-compatible patterns at no charge. Its aging Windows release, unsupported Linux option and stated limitations matter for users needing ongoing support or reliability with longer patterns.
Questions
How much does The Regex Coach cost?
It is free. Commercial use is free, but redistribution or charging money requires written permission.
Which platforms does it support?
The listed platforms are Linux and Windows. The maker provides an unsupported Linux 0.8.5 release that also runs on FreeBSD, and says there is no Mac version planned.
What regex flavor does it use?
It works with Perl-compatible regular expressions and uses CL-PPCRE as its regex engine.
Can it explain or debug a regex?
It can describe a pattern in plain English, display its parse tree, highlight selected parts, and step through matching.
Who makes The Regex Coach?
The site identifies Prof. Dr. Edmund Weitz as the maker.
Facts from The Regex Coach's own pages
- Engine and implementation
- The application is written in Common Lisp and uses CL-PPCRE as its regex engine. · weitz.de, 2 Oct 2026
- Intended users
- The maker says it may be useful to programmers using Perl-compatible regex toolkits such as PCRE or CL-PPCRE. · weitz.de, 2 Oct 2026
- Known limitations
- The regex engine may encounter a stack overflow on relatively long regular expressions, and the maker notes possible issues on Eastern European Windows versions using character set 1250 or similar. · weitz.de, 2 Oct 2026
- Linux availability
- Linux is no longer maintained, but the maker provides the unsupported 0.8.5 release, which also runs on FreeBSD. · weitz.de, 2 Oct 2026
- Live matching
- It shows whether a regex matches a target string and updates other parts of the application in real time when you make changes. · weitz.de, 2 Oct 2026
- Mac availability
- The maker says there is no Mac version and no plan to release one. · weitz.de, 2 Oct 2026
- Maker
- The site identifies Prof. Dr. Edmund Weitz as the maker and lists his address at HAW Hamburg in Hamburg, Germany. · weitz.de, 2 Oct 2026
- Matching stepper
- It can single-step through the matching process performed by its regex engine. · weitz.de, 2 Oct 2026
- Match inspection
- It can highlight captured groups or selected parts of a regular expression in the target string. · weitz.de, 2 Oct 2026
- Privacy and security
- The maker's website privacy notice says its server logs may include IP addresses and other access data, and that anonymous log data is stored separately from personal data supplied by users. · weitz.de, 2 Oct 2026
- Regex explanation
- It tries to describe a regular expression in plain English and can display a graphical representation of its parse tree. · weitz.de, 2 Oct 2026
- Support and warranty
- The program is provided as-is with no warranty, and the maker says not to expect support for older Windows configurations or the unsupported Linux release. · weitz.de, 2 Oct 2026
- Text operations
- It simulates Perl's split and substitution operators. · weitz.de, 2 Oct 2026
- What it does
- The Regex Coach is a graphical application for interactively experimenting with Perl-compatible regular expressions. · weitz.de, 2 Oct 2026
- Windows availability
- The current download is version 0.9.2, and the maker says the program has not changed since 2008; the page reports it worked for the maker on Windows 10 in June 2023. · weitz.de, 2 Oct 2026
Where The Regex Coach stands on Freedom251
- Regular Expression Testers#15 of 23