W3C
validator.w3.org › nu
Ready to check - Nu Html Checker
This tool is an ongoing experiment in better HTML checking, and its behavior remains subject to change · Show sourceoutlineimage reporterrors & warnings onlycheck error pagesUser-Agent Accept-Language
W3C Feed Validation Service, for Atom and RSS
Check the syntax of Atom or RSS feeds · Validate a feed online:
w3 Validator
This Link Checker looks for issues in links, anchors and referenced objects in a Web page, CSS style sheet, or recursively on a whole Web site. For best results, it is recommended to first ensure that the documents checked use Valid (X)HTML Markup and CSS.
Validator.nu
validator.nu
Validator.nu - Nu Html Checker
This tool is an ongoing experiment in better HTML checking, and its behavior remains subject to change · About this checker • Report an issue • Version: 22.3.8
Videos
15:56
How To Validate HTML - Using an HTML Validator
Nu HTML Checker for better web accessibility code checking
04:45
How To Validate HTML - Using an HTML Validator - YouTube
Checking the Validity of HTML files using the NU HTML checker.
01:21
Nu Html Checker - YouTube
W3C Validator alternatives for broken HTML?
Which of w3 validators do you use? What doctype is set on your documents? Give some examples of "valid things" that show errors in validator? More on reddit.com
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May 9, 2025NU HTML CHECKER
Using NU HTML Checker, check by adress - How can I kno what file has the errors? More on forum.freecodecamp.org
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March 24, 2024Outsystems Error Code in Nu Html Checker | OutSystems
I got many error HTML code from Nu Html Checker and actually, I don't know much about W3C Standard because I always use Outsystems Drag and drop and don't mind the rule. I wonder can I change or improve all of them to not error (and warning..)?and how · and this is the customer link project ... More on outsystems.com
Error on Nu Html Checker
Spaces. Paths need to have a valid URL structure. So the file should use underscores to denote spaces, no spaces, or using the entity %20.
So something like src="Black%20cat.jpg"
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November 20, 2022GitHub
github.com › validator › validator
GitHub - validator/validator: The Nu Html Checker (vnu) · GitHub
The Nu Html Checker (vnu) — along with being usable as a standalone command-line client — can be run as an HTTP service, similar to validator.w3.org/nu, for browser-based checking of HTML documents, CSS stylesheets, and SVG images over the Web.
Starred by 1.9K users
Forked by 321 users
Languages Java 91.3% | ANTLR 6.6% | Python 1.4% | TypeScript 0.4% | Makefile 0.3% | Shell 0.0%
Unl
validator.unl.edu
Ready to check - Nu Html Checker
This tool is an ongoing experiment in better HTML checking, and its behavior remains subject to change · About this checker • Report an issue • Version: 25.10.14
W3C
validator.w3.org
The W3C Markup Validation Service
Check the markup (HTML, XHTML, …) of Web documents
Chrome Web Store
chromewebstore.google.com › detail › mpbelhhnfhfjnaehkcnnaknldmnocglk
HTML Validator - Chrome Web Store
This is the of HTML Validator extension for Chrome Manifest V3. It checks the code, syntax, of your HTML 5 pages. HTML Validator for Chrome is a browser extension that adds HTML validation inside Developer Tools of Chrome.
Validator
about.validator.nu
About Validator.nu
Suitable for use with the HTML parser. SVG 1.1 + IRI · SVG 1.1 Full with IRI support (Inkscape cruft not permitted). The service supports a few special pseudo-schema URIs that map to checkers written in a Turing-complete programming language. http://c.validator.nu/table/ Checks (X)HTML table integrity.
Reddit
reddit.com › r/webdev › w3c validator alternatives for broken html?
r/webdev on Reddit: W3C Validator alternatives for broken HTML?
May 9, 2025 -
I've always used the W3C Validator to help find broken HTML elements, but I'm finding it's becoming quite outdated and throwing errors for things that are now valid.
Are there any better alternatives to finding broken HTML elements?
Top answer 1 of 11
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Which of w3 validators do you use? What doctype is set on your documents? Give some examples of "valid things" that show errors in validator?
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The main W3C validator has gone horrifically out of date. WHATWG recommends using the Nu HTML Checker from W3C instead: https://validator.w3.org/nu/ Nothing is more reliable than putting the HTML into a variety of web browsers and checking the console output, though.
Visual Studio Marketplace
marketplace.visualstudio.com › items
HTML Checker - Visual Studio Marketplace
Extension for Visual Studio Code - Checks HTML code using the W3C Markup Validation Service.
Unl
validator.unl.edu › about.html
About the Nu Html Checker
The Nu Html Checker (v.Nu) is an ongoing experiment in better HTML checking, and its behavior remains subject to change.
Whatwg
whatwg.org › validator
HTML Conformance Checkers — WHATWG
Here are the currently known online conformance checkers that track the HTML Standard: Nu Html Checker ·
freeCodeCamp
forum.freecodecamp.org › html-css
NU HTML CHECKER - HTML-CSS - The freeCodeCamp Forum
March 24, 2024 - Using NU HTML Checker, check by adress - How can I kno what file has the errors?
Medium
medium.com › @gulshan_n › streamlining-your-code-top-online-html-validators-for-web-developers-49182f1e2d5c
Streamlining Your Code: Top Online HTML Validators for Web Developers | by Gulshan N | Medium
September 18, 2023 - 2- Nu Html Checker (Validator.nu): Website: validator.nu · Description: Based on the HTML5 specification, this validator offers thorough HTML5 validation and is known for its accuracy. 3- HTML Validator (Validator.w3.org/unicorn): Website: validator.w3.org/unicorn ·
Rocket Validator
rocketvalidator.com › blog › w3c-validator-is-dead-long-live-validator-nu
W3C Validator is dead, long live Validator.nu! · Rocket Validator
July 11, 2017 - Under the hood, a faster, more modern and more robust validator has been in charge of validating HTML5 web pages. Its name is Validator.nu but now it doesn't like to be called that way, and prefers to be called Nu HTML Checker.
Validator
html5.validator.nu
Validator.nu (X)HTML5 Validator - Nu Html Checker
This tool is an ongoing experiment in better HTML checking, and its behavior remains subject to change · About this checker • Report an issue • Version: 22.3.8
OutSystems
outsystems.com › forums › discussion › 59974 › outsystems-error-code-in-nu-html-checker
Outsystems Error Code in Nu Html Checker | OutSystems
I got many error HTML code from Nu Html Checker and actually, I don't know much about W3C Standard because I always use Outsystems Drag and drop and don't mind the rule. I wonder can I change or improve all of them to not error (and warning..)?and how · and this is the customer link project ...
GitHub
github.com › validator › validator › releases
Releases · validator/validator
The Nu Html Checker (vnu). Contribute to validator/validator development by creating an account on GitHub.
Author validator
Maven Repository
mvnrepository.com › artifact › nu.validator
Maven Repository: nu.validator
Maven plugin to validate HTML / CSS / SVG files with the NU HTML Checker (v.NU, https://validator.github.io/validator/)