15 Most Popular HTML Validator Online Tools in 2023

List and comparison of the Best Online HTML Validator Tools:

HTML stands for Hyper Text Markup Language. HTML Validator can be defined as the process to validate HTML web elements for any syntax or format errors.

Why validators came into the picture?

When a developer designs a perfect web page, then he expects the outputs to also be perfect. But unfortunately, the developer had made some syntax errors which went unnoticed.

Now if this code goes for final execution, then it may create some issues. So if the client can remove all the syntax errors if any, then the expected output can be achieved.

HTML validator online tools

Here, comes the HTML Validator Online Tools into the picture. With online tools we can easily remove the syntax errors. There are several tools that are available in the market which we will be discussing in detail in this article.

HTML Validator Online Tools

It plays a vital role for clients who receive information from different resources over the web.

HTML validator is used to validate the syntax errors such as missing quotation marks, open tags and unnecessary blank spaces which as a result avoids the risk of web page looking different from which the developer has developed or it may cause issues while running on multiple browsers.

If we have to validate HTML web elements manually, then it’s a very tough and time-consuming job, when we also have CSS (Cascading Style Sheet) and XML (Extensible Markup Language) in the picture, which includes the risk of more manual errors.

Hence, if the client is aware of HTML validation online process, then he/she can rectify the issues step by step or can globally change it across the application by using find and replace which reduces manual effort, time and errors.

FAQ’s

There are some Frequently Asked Questions by users which are mentioned below for your reference:

Q #1) What is an HTML Validator?

Answer: HTML Validator is an online tool which is used to validate the HTML syntax like open tags or unnecessary blanks of the application before the final deployment so that there is no application flow disruption during execution.

Q #2) Why should we validate the HTML web-pages?

Answer: Nowadays every website has dynamic pages which include many functionalities such as HTML, XML, CSS etc. So in order to keep the code error free and maintain a continuous flow of the application, a web page should be validated.

Q #3) What is the working mechanism of HTML Validator Tools?

Answer: It works on a simple mechanism of validation program to mark errors, and provides the option to choose the errors one by one or make a complete check of the application and directly replace all the errors.

Q #4) What can be a possible effect if the HTML pages are not validated?

Answer: There may be a possibility that the current code works fine in one browser but it shows some unexpected outcome in another browser, so in order to make sure that it is compatible in all platforms, HTML validation is advised before deployment.

Below is the list of best HTML Validators with their features, price and some more factors which would help a user to decide which is the best Validator Online for their organizations.

The Validators are divided into four categories:

  1. Free HTML Validators
  2. Premium Validators
  3. Browser extension
  4. Online HTML Validators

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Best Free HTML Validators

These tools are helpful for those clients and organizations which don’t have enough finance and just want to learn the coding or for those who just want to give a try before starting any website on their own.

Below mentioned are the free tools:

#1) The Nu HTML5 Validator

2.The Nu HTML5 Validator

The Nu HTML5 is a popular HTML 5 Validator Online tool. Nu HTML5 helps to scan the complete application and find out all the syntax errors in the application.

It helps to validate all the HTML, CSS and XML syntax with NVDL drove validation and RESTful Web Service API. It has a simple UI and the functionality orientation is good.

Core Features:

  • It has the Pitch which has HTML5 Validation, RELAX NG Validation, Schematron 1.5 validation, NVDL has driven validation and HTML5 parsing.
  • It is best suited for validating live data, copied text or any uploaded data in the web.
  • For simplicity, the HTML5 facet only shows UI for validation by URL.
  • It has a powerful configuration mechanism which uses schemas, parser, be lax about HTTP content type, shows image report and source.
  • It also supports web service API to the client who wants an alternate mode of input for the application.

Price:

  • Nu HTML5 is available on the internet for free.

Verdict:

  • NU HTML5 is best suited for validating live data, copied text or any uploaded data or information in the web.

Official Website: Nu HTML5 Validator


#2) Aborla HTML Validator

3.Aborla HTML Validator

Aborla is a popular online validator and is trusted by many giants.

Aborla HTML, XHTML and XML validator is developed on language Tidy and PHP 5. Aborla authorizes the client to verify and automatically repair HTML, XHTML, and XML. Aborla tool also helps you to convert HTML format documents into XHTML format easily with a single button.

It also helps the client to check the syntax of the code for the entire application easily. Aborla also checks the grammatical errors and helps to correct the application flow by fixing bugs.

Core Features:

  • Aborla’s sole feature is that a user can easily convert an HTML doc to XHTML doc with just a single click.
  • Supports multiple languages which are approximately 16 in number.
  • Has a powerful customization feature with the help of which a user can hide comments, indent blank spaces and has the ability to validate the complete code as per uploading and URL.
  • It also has a nice viewing feature with the help of which a user can view the bugs or source code alone.

PRICE:

  • Aborla is available on the internet for free.

Verdict:

  • Its sole feature is that user can easily convert HTML doc to XHTML doc with just a single click.

Official Website: Aborla


#3) Dr. Watson HTML Validator

4Dr. Watson- HTML Validator online tool

Dr. Watson is a famous Validator online tool which is preferred for its simple features.

Basically, Dr. Watson is a kind of debugger that lets the computer and client know if there is an error within the program application.

With the help of the information and logs provided by Dr. Watson, it gets easier for the technician to know the root cause of the error. Dr. Watson also creates a text file with all the information.

Core Features:

  • The best feature for clients is, it is free of cost with many good features.
  • It demands the URL to refer a page and clones it straight away from the present server itself.
  • It not only validates HTML syntax but also many other things like different search compatibility, the speed of download, and checks if the provided link is genuine or not.
  • With validating HTML syntax, a user can also simultaneously validate grammatical error, link validations etc.

PRICE:

  • Dr. Watson is available on the internet for free.

Verdict:

  • It not only validates HTML syntax but also many other things like different search compatibility, the speed of download, and checks if the provided link is genuine or not.

Official Website: Dr. Watson


Premium HTML Validation Tools

Premium validators come with tools cost and license. It has some extra features which are required by the organizations for reliability and security.

#4) Total HTML Validator

5.Total Validator

Total Validator as the name suggests is a complete package for validating HTML and CSS syntax.

Total Validator makes sure that the user is able to access the pages, and performs the grammatical check, and checks the unverified links.

It also has the potential to validate the client’s website application in just a single click. Total Validator has a cross-platform support, DOM Validation and also support login forms.

Core Features:

  • It can validate both HTML & CSS easily.
  • It also provides grammatical checks.
  • It supports cross-platform functionality.
  • It has more HTML tests, more validations and is very quick in response.
  • It automatically provides all the required updates.

PRICE:

  • Total Validator is priced at US $ 47 for Pro License.

Verdict:

  • It can validate both HTML and CSS which is an added advantage for any client.

Official Website:  Total Validator


#5) CSS HTML Validator

6. CSE HTML Validator

CSS HTML Validator is very popular due to its all-around features and the area it covers for validations.

CSS HTML Validator is based on a powerful mechanism that is simple and user-friendly. CSS HTML has the ability to validate functionalities like HTML, CSS, XHTML, JavaScript, Grammatical Errors, PHP syntax etc.

It reduces the loading of website failures, thereby saving time and increasing the productivity which in turn increases the profit.

Core Features:

  • The important feature of CSS HTML Validator is the multi-functionality validation which includes HTML, CSS, XHTML, JavaScript, Grammatical Errors, PHP syntax etc.
  • It has a batch wizard feature which helps the client to validate files and URLs at once.
  • It uses HTML Tidy tool to automatically fix certain HTML issues.
  • It has a built-in editor which highlights the issues so that it can be corrected early.
  • It has an integrated web browser so that the sites can be browsed and validated at the same time.

PRICE:

  • CSS HTML Validator comes with Home, Pro, and Enterprise editions at US $69, US $129, US $299 respectively

Verdict:

  • The best feature of CSS HTML Validator is its multi-functionality validation which includes HTML, CSS, XHTML, Java Script, Grammatical Errors, PHP syntax etc.

Official Website: CSS HTML Validator


#6) Rocket Validator

7. Rocket Validator

Rocket Validator is a famous online tool which comes with good features to handle big web applications for multinational companies.

It works on its own server, so need to install in the local machine.

Powerful HTML validation feature as it uses Nu HTML Checker by the W3C. It is reliable and provides quick responses to the request made by the clients.

Core Features:

  • It has good accessibility validation as it uses ax-core accessibility engine.
  • It has muting rules which allow the user to select which issues can be muted temporarily.
  • High Configurable rate limits and scheduling, as auto validation of sites, happen as soon as the client deploys the new version.
  • Additional features like validation charts, deep link crawling for validating the submitted pages, XML Sitemap Parsing.
  • It provides a summary report, per-url report, broken link checkers, speed and shareable reports.

PRICE:

  • Rocket Validator comes with Basic Weekly plan and Pro Weekly Plan at a price of US $9 and the US $ 12 respectively.

Verdict:

  • The best feature of Rocket Validator is its Muting Rules which helps the client to select or prioritize the issues based on urgency.

Official Website: Rocket Validator


Browser Extensions

These tools are just an extension to the installed browser like Chrome or Firefox which in turn provide the ability to validate the HTML pages at the same place and no specific tool is required.

It checks the HTML5 pages, XML, CSS, grammatical and syntax errors.

#7) Firefox HTML Validator

8.Firefox HTML validator

This is one of the trusted browser extensions for HTML validation.

It is nothing but just an extension to Mozilla which includes HTML validation within Firefox and Mozilla. In the status bar, there is an icon on the form where all the errors are displayed.

It can validate both the HTML sent from the server as well as which is inside memory. Basically, this Firefox extension is based on Tidy and Open SP, so as a result, the client can validate the HTML locally in their system.

Core Features:

  • Its an extension to Mozilla, so if the client uses it on any operating system like windows or MAC it gets easy to validate HTML as soon as we visit the application site.
  • It has a strong feature of showing all the errors on an icon in the status bar.
  • It supports many numbers of languages, which is approximately 17 types and this is an added advantage.
  • If a client wants to make a track of the error then they can see the source code for this.

PRICE:

  • It is available on the internet at a free of cost.

Verdict:

  • Its best feature is showing all the errors on an icon in the status bar which is present on the web page. It makes the work a lot easier.

Official Website: Firefox HTML Extension


#8) HTML Validator for Chrome

9. HTML Validator Online Tool for Chrome

It is of a very small size, hence it runs fast. It is nothing but just an extension to chrome for checking the code and syntax of HTML5 pages.

As we know its an extension which is inside the developer tools of chrome. All the error details can be seen in the developer tool itself for faster fixing. It is also based on Tidy. It also has an automatic clean up button for cleaning up the web page from errors.

Core Features:

  • It has a powerful mechanism for HTML5 validations.
  • It also shows additional warnings for things that may or may not be an issue and also provides the ability to filter out the issues.
  • It supports multiple languages.
  • Here all the details can be seen in the chrome developer tool.

PRICE:

  • It is available on the internet free of cost and can be directly added to the client’s chrome browser.

Verdict:

  • The best feature of Chrome Validator is that it shows additional warnings for things that may or may not be an issue and also provides the ability to filter out the issues which in some scenario proves very vital for clients.

Official Website: HTML Online Validator for Chrome


#9) Skynet

10. SKYNET HTML VALIDATOR

It is also a popular validator with many good features and it comes under the Mozilla brand.

It is basically a browser extension which adds HTML validation inside Firefox and Chrome browser. Here also the number of errors present can be seen in the icon present in the ADD-ON bar.

The details of errors can be seen in the source code. This extension is also based on Tidy and OpenSP. For a fact, these two algorithms were originally developed by the W3C company.

Core Features:

  • HTML validation can be done while browsing itself and also if the webpage contains HTML iframes then the results can be seen in home page itself.
  • It has a strong view source like Tidy which validates the HTML code and shows the result like a compiler, the screen is divided into parts for better view and validation is done based on the source code.
  • It supports many different languages.
  • It has an additional clean up feature, and here the data is not sent to any third party server.

PRICE:

  • It is available on the internet at a free of cost and can be directly added to the client’s chrome and firefox browser.

Verdict:

  • It has a good additional clean up feature, and here the data is not sent to any third party server which in turn makes the data secure.

Official Website: Skynet


Online HTML Validators

Online validators are efficient in validating syntax for HTML, CSS, XML, etc.

It uses the W3C standard for validating the pages online. It checks if the application is browser compatible or not by removing the maximum syntax errors from the code.

Mentioned below are some top online tools:

#10) WDG Validator

11.WDG HTML Validator Online Tool

WDG is a powerful HTML Online Validator Tool due to its features.

It checks the application code as per the formal standards published by W3C for both HTML and XML. Its also serves the purpose of checking spelling and proofreading for grammar and syntax.

It is more specific as it deals with machine language. Just enter the URL of HTML application to do the validation. It also has a batch mode. Here we can validate the files present in the system.

Core Features:

  • WDG HTML online validator is very fast and also gives information about the active live pages to the client.
  • It is open source and is available in English and French Language.
  • It provides warnings for harmful HTML code, unclosed start tags, and end tags, blank start and end tags, net enabling start tags etc.
  • It also gives information about undefined references such as &#147 and &#153 and uses a special SGML declaration when the document refers to custom DTD.

PRICE:

  • It is available on the internet at a free of cost.

Verdict:

  • The best feature is that it provides warnings for harmful HTML code, unclosed start tags and end tags, blank start and end tags, net enabling start tags etc.

Official Website: WDG


#11) Freeformatter Validator

12.FREEFORMATTER HTML VALIDATOR

FreeFormatte tool is well efficient in validating the HTML files in command against the W3C standards described and makes sure that the code is written as per the standard guidelines and best practices.

It gives the client a number of choices as in which format they want to validate their application like JSON, HTML, XML, SQL, Batch Formatter, encoder and decoders, code minifiers and converters, cryptography and security, string escapers, utilities, and web resources etc.

Core Features:

  • It has a simple and user-friendly UI.
  • It is efficient in finding the missing HTML tags in the application.
  • It also detects stray characters, duplicate ID’s, invalid attributes and other recommendations.
  • The client just has to only copy the documents in the dashboard and Freeformatter takes care of the rest.

PRICE:

  • It is available on the internet at a free of cost.

Verdict:

  • The best feature is that it can find missing tags in HTML and the clients have to only place the documents and the remaining part is automatically taken care by Freeformatter.

Official Website:  Freeformatter


#12) W3C Markup Validation Service Online Tool

13.W3C Markup Validation Service Online Tool

W3C Markup Validation is an open source and free service provided by W3C to check the validations of the documents. It is versed in checking HTML, XHTML, MathML, SMIL, SVG , SGML, XML DTD validations for the applications.

As it provides so many validation features, it is trusted by many good organizations. It comes under ISO/IEC 15445 and ISO 8879 international standards.

Core Features:

  • Its an open source HTML Validation service which validates HTML, XHTML, Mathml, SMIL, SVG , SGML, XML DTD formats.
  • In this tool, we have the access to enter the URL of application for validation.
  • Here we can also upload files and copy paste parts of HTML for validation.
  • It is not good in the validation of grammatical errors.
  • It has a powerful validating mechanism and a good UI too.

PRICE:

  • It is available on the internet at a free of cost.

Verdict:

  • The best feature is that it is an open source HTML Validation service which validates different formats of application like HTML, XHTML, MathML, SMIL, SVG, SGML, XML DTD and this is not provided by any other HTML validator Tool at a free of cost.

Official Website: W3C Markup Validator


#13) JSON Formatter

14. JSON formatter

JSON Valitor Online tool helps the client to validate their JSON data. It also provides a kind of tree view to the client so that they can navigate through the formatted JSON data. It is a powerful tool and is open source too.

JSON Formatter is a very unique tool for formatting JSON, converting JSON to XML, CSV, and YAML. It can be used as a JSON validator, JSON editor and JSON viewer. It supports multi-platform and works well on Windows, Mac, Linux, Chrome, Safari, Edge etc.

Core Features:

  • JSON Formatter has a good documentation and UI.
  • It helps to validate JSON online with error messages and supports printing of JSON data.
  • It has a feature to support for indentation like 2 level or 3 level.
  • It always stores data locally for the previous formatted JSON.

PRICE:

  • It is available on the internet at a free of cost.

Verdict:

  • It has a unique feature which no other tool provides. It supports indentation like 2 levels or 3 levels.

Official Website: JSON Formatter Validator


#14) W3schools Validation Online Tool

15. W3schools Validation online Tool

W3Schools is one of the top contenders among the Validation tools.

It is used to check the correctness of w3.css. It provides validation warnings for CCs1,CSS2, CSS3, CSS4 properties. It uses vendor extension to support the older browsers. It supports multiple platforms like chrome, safari, opera, firefox etc.

Core Features:

  • It has a perfect UI and good documentation.
  • It is well versed to validate all the CSS properties and also provides support for the older outdated browsers.

PRICE:

  • It is available on the internet at a free of cost.

Verdict:

  • It has a good validation mechanism as well as browser support extension.

Official Website: W3schools Validation


#15) Validome Validator Online Tool

16.VALIDOME VALIDATOR ONLINE TOOL

Validome Validator is a powerful HTML validating online tool.

It helps the web searchers to check their syntax and format with reliable, high-speed validation service against the followed official standards. If the code is followed as per the standards, then it reduces half of the risk with browser issues and releases. It helps to validate HTML, XHTML and WML validation.

Core Features:

  • It has strong documentation and is capable of validating HTML, XHTML and WML formats.
  • It provides standalone grammar validator for XML DTDs and Schemas.
  • It provides advanced feed validator for RSS and Atom.
  • It helps to expose and repair barriers to make it accessible.
  • It also validates google sitemap on XML conformity and makes the site more readable.

PRICE:

  • It is available on the internet at a free of cost.

Verdict:

  • The best feature is that it helps to expose and repair barriers to make it accessible.

Official Website: Validome Validator


Conclusion

We have covered almost all the top best free HTML Validator Online tools along with top features, pricing, and official website.

We also came to know why HTML validator plays an important role in any organization. However, just to conclude I would tell the best benefits and advantages of using Validator Tools which has vital effects for increasing the company’s profit.

Validator Tool Benefits:

  1. Increased Web Accessibility: If the HTML code is clear, then it can avoid certain blocks or issues which restrict the user to search the complete site.
  2. Page Loading is faster: If the unwanted code is removed, then it makes the code base small so the application loads faster.
  3. Load shed on servers: Good and error-free code reduces the space required and the cost as well.
  4. Compatibility of Browsers: If the code is validated for compatible issues then it avoids the risk of any browser issues.

Based on the points and price mentioned above, you can decide which validator tool is best suited for your organization.

=> Contact us to suggest a listing here.