best RegEx tester

The programming community doesn’t refer to it as a regular expression because it’s a bit mouthful. All the programmers refer to this as Regex. Regex is not a programming language. There is a misconception that we need to learn programming languages such as Java, Python, etc. to use Regex. The truth is that it is not necessary. 

All the programming languages can use a regular expression. Some can be used as default while some need to download some packages, like third-party packages. Apart from that, all the programming languages like Python, Ruby, Java, Javascript, PHP, etc. have the capability and ability to use Regex.

So the question that arrives is what is Regex? 

About Regex

Regex is simply a pattern matching device. Regular Expressions or as it’s regularly known – RegEx is any arrangement of characters that can be utilized as a pattern to look for characters or strings.  

For instance – to decide whether a string or expression contains “apple” we can utilize the regex “/apple” to look inside the string. Further, we can utilize “/[0-9]” to check if a given string contains a number somewhere in the range of 0 and 9.

What programming language should I be learning to master the Regex? The answer is choosing whatever language you know since we all know regex is neither a programming language nor a plugin. It is just a way of finding things. There is no such thing as the best programming language with regex. 

How Much Time Should I Spend with Regex?

Regex testerBefore you move on to that, know that Regex is hard and I believe that it is not easy to learn and write regex scripts. People have spent days and sometimes many hours just writing a simple regex script but this is super powerful yet hard, and time-consuming as well.

So how much time should you be spending learning regex? Now, it depends on what you want to do with Regex: in case you are into cybersecurity or maybe network administrator at Linux. Learning Regex alone will take you to the next level, but again if you are just a regular web developer, say iOS or Android developer, then it’s not necessary to go in-depth. 

Regular Expressions and their utilization 

1. We have all utilized “CTRL + F” commonly to look inside a report to locate a specific word or an expression or an articulation. This is a basic illustration of where Regular Expressions can be used. 

2. There can be a lot of patterns like that you might have noticed that some website pushes you that you should use the password in uppercase lowercase some letters and some special characters as well. This is all done using regular expressions forcing a user to write the correct format of the email, to use a very secure password, and entering a credit card number in the right format. These are just examples where regular expressions are used but it can go way beyond this. 

3. Regular Expressions are broadly utilized for an assortment of purposes in cutting-edge web-related tasks. Few examples where regular expressions are frequently used: 1 validation of web forms  2 lexical analysis in IDE’S 3 document editor 4 text editors 5 web search engines. 

There are many more instances where Regex is utilized, they are Normally utilized standard articulations: 

Regular Expressions are generally utilized over the Internet. From structure approvals to looking into information containing a specific catchphrase or watchwords, Regular Expressions are practically indivisible from cutting-edge processing applications.  

We should take a gander at some recognizable instances of the utilization of regular expressions. 

1. Coordinating a telephone number:

We should perceive what is the example of a telephone number utilized in India. The Country Code starts things out. It ordinarily contains a “+” character followed by the number 91, which is the nation code for India. Likewise, Indian telephone numbers, for the most part, start with 6, 7, 8, or 9. This is then trailed by 9 different digits.  

So a substantial regex for an Indian wireless number would be as given.  


2. Testing the strength of passwords

Most sites prescribe us to give a solid secret key that contains a blend of numbers, capitalized and lowercase characters, and images. Likewise, there must be a base number of characters – 6 or 8. This is done with the goal that the secret word turns out to be difficult to break. 

Any secret word adhering to this standard can be created or approved for secret phrase strength utilizing a normal articulation. 


3. URL Matching

URLs are the most widely recognized approach to utilize the web and rapidly visit the page we need. Pretty much every site has a URL. Henceforth, every URL is normalized and follows an unequivocal example. Each URL either follows the HTTP or the HTTPS convention followed by “://” and the “www” frequently. At that point, the name of the site is followed by a .com or .net or .organization and so forth. 

To test the legitimacy of a URL we can utilize a regex like the one given underneath. 


4. Date and Time designs

Date and time designs are normally utilized across the web. There are numerous configurations of dates utilized by an assortment of software or applications or even frameworks. Dates ought to consistently be utilized in a configuration that makes it usable for the client or the application that is attempting to understand it. 

A date in the organization dd-MM-YYYY can be approved by utilizing a regular expression which can be as given beneath. 


Presently, we should investigate a portion of the online RegEx apparatuses that can be convenient to assemble and investigate. 

On the off chance that you need to get familiar with regular expressions, their models, and progressed utilizations, here is a rundown of sites that you can generally allude to: 

List of RegEx testers

1. RegEx101

regex testerRegex101 is a fantastic reference manager and online regex tester with an intelligent apparatus for making your standard articulations. It can assist you when you are just getting started with Regex. 

By utilizing this, we can test RegEx for the underneath dialects. 

  • PCRE (PHP)
  • ECMAScript (JavaScript)
  • Python
  • GoLang

It gives support to RegEx functionalities like a match, replacement, and unit tests. Aside from this one can save the old tried RegEx. 

2. FreeFormatter RegEx analyzer 

FreeFormatter is JavaScript-based regex tester which utilizes the XRegExp library for upgraded highlights. It encourages testing a RegEx against a match just as supplanting a match. It underpins beneath banners, which can be utilized relying on the necessity while testing a RegEx: 

  • I – Case-insensitive
  • m – Multiline
  • g – Global (don’t stop at the principal coordinate)
  • s – Dot coordinates all INCLUDING line breaks (XRegExp as it were).

 3. Regex Crossword 

regex testerIf Regex and riddles interest you, this is the site to go to. It has a great time and intuitive riddles. Streamlined for telephones and settling RegEx puzzles in a hurry. There is a bit by bit instructional exercise, showing you the various images and RegEx designs. It twists your brain around cubistic 2D palindrome RegEx puzzles. There is a wide scope of RegEx puzzles with troubles from novice to master.  

4. RegExr 

RegExr is a regex tester for getting your hands filthy with Regex. You can compose regex, coordinate examples, and have a good time with this Codepen identical for Regular Expressions. 


  •   Supports JavaScript and PHP/PCRE RegEx.
  •   Syntax highlighting, cheat sheet, contextual help.
  •   Save and offer articulations with others.
  •   Results update progressively as you type. 
  •   Turn over a match or articulation for subtleties. 
  •   Approve designs with set-ups of Tests.  

5. Pythex 

pythexIt is a Python-based regex tester and analyzer. Pythex is a speedy method to test your Python standard articulations. It accompanies four banners precisely:

Overlook Case, Multiline, DotAll, and Verbose.

6. Debuggex 

It is JavaScript-based online regex tester and underpins Regex for Python and Perl Compatible Regular Expressions(PCRE). Utilizing this online device, we can insert our RegEx into StackOverflow. It gives an office to share the RegEx result by making a novel connection against each RegEx test. 

7. RegEx Tester 

This free standard articulation analyzer allows you to test your ordinary articulations against any section of your decision and obviously features all matches. Utilizing this, we can save the old tried RegEx for future reference. Additionally, it underpins JavaScript and PCRE RegEx. 

8. WebToolKitOnline RegExTester  

regex testerWeb Toolkit contains a bunch of utility devices, RegEx analyzer is one of them. We can include our RegEx here and can test it against a worth. It likewise gives an office to supplanting, coordinating, and replicating the articulations. Aside from this, it also gives a switch to play out a case-delicate and worldwide match.

9. Rubular 

Rubular is a Ruby-based standard articulation manager. The platform is a robust RegEx tester. It supports and uses the Ruby 2.5.7 form onwards.

10. Extendsclass 

extendsclassExtendsClass is a tool compartment for designers. It is a RegEx tester backing to the following dialects. 

  • JavaScript 
  • Python (3.4) 
  • Ruby (2.1) 
  • Java (JDK 14) 
  • PHP (7) 

 Presently, equipped with this information, we will now decode some regular expressions.

  • ^([a-zA-Z0-9_\-\.]+) implies we are searching for a string that begins within any event at least one capitalized or lowercase alphanumeric character, underscores, hyphens, or dabs. For example, anything that appears to be like user_name.01 will coordinate the example. We should recollect that here, you don’t have to incorporate all the images simply any one character in [a-zA-Z0-9_\-\.] will do. 
  • The @ character matches for a solitary event of @. Adding to the past model, something like user_name.01@ will fit. 
  • ([a-zA-Z0-9_\-\.]+) is like the primary point. It also implies that we are searching for a string that contains in any event at least one alphanumeric character, underscores, hyphens, or dabs. Adding to the model, user_name.01@gmail will fit here. 
  • As you would have just speculated, we are indicating an email design. Proceeding onward, \. matches the single “.” character. On the off chance that we proceed with the continuous model, something like user_name.01@gmail.  
  • ([a-zA-Z]{2,5})$ this implies that the string should end with 2 to 5 letters in order characters either capitalized or lowercase. On the off chance that we add .com to the past model, we can get, which is the normal example of an email string.  

Consolidating the above information, we can see that we are looking for an email id string. Presently we can utilize this articulation to approve any email. If our test email id coordinates this example, we can say it is a legitimate email id. 

I hope you got a solid understanding of what regex is and where it is used.

Considering all the advantages of regex, you may feel as if you can solve all the string problems, once you get regex under your belt. Well, you might be wrong there.

Here are some limitations of regular expressions:

1. There is no regex representation for a bundle of valid JavaScript programs. We cannot check if JavaScript is syntactically correct since there will never be a regular expression pattern.

2. Regex only deals with nested structures of arbitrary depth. So they are inherently non-recursive. Examples of nested structures are JSON, palindromes, X ML. A pattern can be constructed to match a nested structure up to a certain depth but not that matches arbitrary depth.

3. It is complex, and often there is a trade-off between performance and maintainability. Correctness is said to be a conscious decision. 

 4. Be very cautious while using regular expressions since you may get into legal trouble.

These are some of the limitations and there is a long to go. On the web, there are hundreds of other resources that can help you understand regex. I also recommend that if you find some good books related to programming languages then just go ahead and buy. Why? It is not investing in learning. Because it’s something that you invest in yourself.


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