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Debuggex

debuggex.com

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Spec score 9.1 #2 of 23 in Regular Expression Testers

What it is

Debuggex is an online visual regex tester for JavaScript, Python, and PCRE. It offers visual and text modes, a step-through debugger, and pattern explanations for examining expressions. Users can add unit tests to check matches and subgroups as a regex changes, and browse a repository of pre-built expressions that includes tests. The service generates code snippets, saves patterns, and creates links that reopen expressions; expressions can also be embedded in StackOverflow answers. The Free plan costs nothing and includes two saved unit tests per regex and ten public expressions. Basic costs $5 a month, while Pro costs $15 a month. Enterprise has no listed price and includes options such as private server deployment, denial-of-service prevention, flexible user counts, an OEM license, and on-site training. The free tier excludes snippets based on expressions from the library. The privacy policy says saved or shared expressions can be viewed by anyone with the link, and previous versions are stored after updates. Debuggex is available on the web.

Spec sheet

What it does
Debuggex is an online visual regular-expression tester and debugger for JavaScript, Python and PCRE.Read 15 Oct 2026 · debuggex.com
Product
Debuggex describes itself as an online visual regex tester for JavaScript, Python, and PCRE.Read 30 Sep 2026 · debuggex.com
Integrations
The site offers an embed option for StackOverflow and lists Google Analytics and Mozilla Persona in its privacy policy.Read 30 Sep 2026 · debuggex.com
Privacy
The privacy policy says Debuggex does not sell collected user data to third parties without express permission and stores only the account email, not the password.Read 30 Sep 2026 · debuggex.com
Built-in testing
Users can add unit tests and check whether matches and subgroups behave as expected when a regex changes.Read 30 Sep 2026 · debuggex.com
Cheatsheet
A built-in flavor-specific regex quick reference covers operators such as groups, assertions, quantifiers, anchors and escapes.Read 15 Oct 2026 · debuggex.com
Code generation
Repository expressions can be compiled into a language-specific code snippet from the interface.Read 15 Oct 2026 · debuggex.com
Code snippets
The product can generate a code snippet from a regex, while the free tier excludes snippets using expressions from the library.Read 30 Sep 2026 · debuggex.com
Company identity
Founder Serge Toarca identifies the incorporated business as Debuggex Inc. and calls Debuggex his first product.Read 15 Oct 2026 · toarca.com
Early commercial traction
The founder later wrote that Debuggex sold one $4,000 licence in its first six months and generated about $25 per month in subscriptions.Read 15 Oct 2026 · toarca.com
Early outage
In a 26 April 2013 founder post, Debuggex reported two brief outages affecting fewer than ten users at the time.Read 15 Oct 2026 · toarca.com
Enterprise deployment
The Enterprise plan offers optional private-server deployment and an optional OEM licence.Read 15 Oct 2026 · debuggex.com
Expression library
The product includes a searchable library of saved expressions and can generate snippets from expressions.Read 15 Oct 2026 · debuggex.com
Expression visibility
The privacy policy says saved or shared expressions are viewable by anyone with the link and that previous versions are stored after updates.Read 30 Sep 2026 · debuggex.com
Independent listing
AlternativeTo describes Debuggex as a freemium, proprietary website in the development category and lists more than 25 alternatives.Read 15 Oct 2026 · alternativeto.net
Launch timing
The founder says he launched the regex tester about two months before his 26 April 2013 article, placing the initial launch in early 2013.Read 15 Oct 2026 · toarca.com
Licence
Debuggex states that its own software is not open source.Read 15 Oct 2026 · debuggex.com
Limit: commercial perception
A Reddit discussion included a complaint that Debuggex felt commercial and lacked a quick reference, although another commenter linked to its quick reference.Read 15 Oct 2026 · reddit.com
Limit: interface age
Scraping.Pro characterized the interface and feature set as dated compared with newer regex testers.Read 15 Oct 2026 · scraping.pro
Limit: named groups and flags
Webscraping.pro reported limited named-group functionality and support for only a limited set of regex flags.Read 15 Oct 2026 · webscraping.pro
Limit: paste workflow
A Stack Overflow commenter wished Debuggex allowed pasting text directly into the tool.Read 15 Oct 2026 · stackoverflow.com
Limit: workflow breadth
Scraping.Pro’s review says Debuggex is thinner than newer tools for substitution previews, broad explanations and code generation, and lacks substitution testing.Read 15 Oct 2026 · scraping.pro
Live matching
Matches and non-matches update in real time while the expression and test text are edited.Read 15 Oct 2026 · debuggex.com
Praise: community users
Reddit commenters repeatedly described the tool as useful for learning, immediate visual feedback, explaining regexes and generating code.Read 15 Oct 2026 · reddit.com
Praise: learning
A C.W.K. regex lesson recommends Debuggex when learners need to understand a complex pattern through its railroad diagram.Read 15 Oct 2026 · creativeworksofknowledge.com
Praise: unique diagrams
Scraping.Pro’s 2026 review says Debuggex remains unusually strong for showing a tangled pattern’s structure as a railroad diagram.Read 15 Oct 2026 · scraping.pro
Praise: visualisation
Webscraping.pro praised the central visual diagram, live highlighting and slider-based step-through as useful for understanding complex matches.Read 15 Oct 2026 · webscraping.pro
Privacy collection
The privacy policy says Google Analytics is used for anonymous usage statistics and that authentication stores email while Mozilla Persona handles passwords.Read 15 Oct 2026 · debuggex.com
Regex repository
Debuggex offers a repository of pre-built expressions, with unit tests for repository regexes.Read 30 Sep 2026 · debuggex.com
Repository launch
Debuggex announced its composable regex repository on 17 September 2013, initially describing almost one hundred pre-built expressions.Read 15 Oct 2026 · debuggex.com
Repository unit tests
Each repository expression was described as having a test suite intended to preserve backwards compatibility.Read 15 Oct 2026 · debuggex.com
Saved-expression visibility
Saved or shared expressions are visible to anyone who has the link, and previous versions remain stored after updates.Read 15 Oct 2026 · debuggex.com
Sharing
Debuggex creates shareable links that reopen the exact expression and test-string state.Read 15 Oct 2026 · debuggex.com
Stack Overflow embed
The site can generate embed code for a diagram and link suitable for Stack Overflow answers.Read 15 Oct 2026 · debuggex.com
Support contact
The site lists [email protected] as its contact address.Read 30 Sep 2026 · debuggex.com
Terms ownership
Users retain ownership of saved information but grant Debuggex a broad licence to use shared intellectual-property content until deletion, subject to forking.Read 15 Oct 2026 · debuggex.com
Third-party components
The maker lists open-source dependencies including AngularJS, D3.js, jQuery, Node.js, node-pcre, PCRE, Pyramid and Underscore.js.Read 15 Oct 2026 · debuggex.com
Unit tests
Users can add expected-match and expected-non-match tests, with passing and failing results shown in the interface.Read 15 Oct 2026 · debuggex.com
Visual debugging
The product provides visual and text modes for examining regular expressions.Read 30 Sep 2026 · debuggex.com
Visual mode
The web interface renders a regular expression as a visual diagram and also provides a text mode.Read 15 Oct 2026 · debuggex.com

Plans and prices

Free Free per month Regex visualizer · Regex debugger · JavaScript engine · Python engine (beta) · PCRE engine (beta) · code snippets · 2 unit tests per regex · 10 public expressions Read 15 Oct 2026 · debuggex.com
Basic $5 a month per month 5 unit tests per regex · unlimited public expressions · 20 private expressions · plain-English explanation · regex replace · unit-tested repository · repository composability Read 15 Oct 2026 · debuggex.com
Pro $15 a month per month Unlimited unit tests · unlimited private expressions · composability using any expressions · performance debugging · unit-test coverage Read 15 Oct 2026 · debuggex.com
Enterprise Priced on request Denial-of-service prevention · flexible user counts · optional private-server deployment · optional OEM licence · optional on-site training Read 15 Oct 2026 · debuggex.com

Every Debuggex plan and price →

Strong points and limits

Strong points

  • Visual and text regex modes
  • Tests matches and subgroups as expressions change
  • Supports JavaScript, Python, and PCRE
  • Share links reopen the same expression

Limits

  • Free plan saves only two unit tests per regex
  • Free plan allows ten public expressions
  • Linked expressions are viewable by anyone with the link

Who it suits

Debuggex suits developers who write or inspect JavaScript, Python, or PCRE regular expressions. Its unit tests and shareable links can support people checking expressions as they change or sharing them with others.

Verdict

Debuggex combines regex visualization, testing, and sharing in a web tool, with Free, Basic, and Pro plans at listed monthly prices. Readers should note the free-tier limits and that linked expressions are viewable by anyone with the link.

Where Specifiction places it

Alternatives to DebuggexAll alternatives →