About HTML Validator

What is CSE HTML Validator?

CSE HTML Validator for Microsoft Windows is a powerful, easy to use, user configurable, and all-in-one HTML, XHTML, and CSS checker that includes a link checker, spell checker, accessibility checker, built-in editor, and also checks for search engine issues.

Unlike other HTML validators and checkers, CSE HTML Validator features an unusually powerful custom syntax checking engine that is specifically designed to check HTML, XHTML, CSS and more; and with the built-in editor you can make changes to your documents right inside of CSE HTML Validator.

CSE HTML Validator (also referred to as HTML Validator) is an important part of an HTML development environment. Before publishing web pages, especially pages created manually or with a "dumb" HTML editor, you should check them for syntax errors, misspelled words, and broken links. CSE HTML Validator functions as that checker, helping to make sure that your web pages are written in correct syntax so that they are viewed as intended in a variety of web browsers.

NOTE: CSE HTML Validator is not a DTD validator. However, the standard and higher editions include nsgmls, a DTD validator.

You may also want to read the Supported Languages and System Requirements topics.

Why is CSE HTML Validator Useful?

CSE HTML Validator helps you eliminate website problems that cause visitors to abandon websites. It increases your productivity and saves you time and money. If you don't check your web pages for problems, then there's a much greater chance that your visitors will encounter them, especially if they use a web browser that is different from the one you used to create and check your web pages.

Do you want a good search engine ranking? Most people want their sites to be listed in a good position on search engines. Web pages that are free of problems have a better chance of a higher ranking on search engines than web pages that contain problems. This is because search engine spiders can get confused and may not read a web page's content correctly if it contains certain problems, especially significant structural errors.

CSE HTML Validator can detect most, if not all major structural problems. In addition, the standard and higher editions display messages that are designed to help improve a website's search engine rankings, such as checking meta description and keyword tags. Following the search engine advice given by CSE HTML Validator could very well result in a significant improvement in a website's search engine rankings. See the Search Engine Page in the Validator Engine Options.

Do you want to automatically fix HTML or change your HTML to XHTML? The standard and higher editions include an HTML Tidy Tool. This tool is capable of automatically fixing certain issues and changing HTML to XHTML. In addition, it can also format ("pretty print") your HTML/XHTML pages to be more readable.

Finally, it is important to know that checking your web pages for correct syntax cannot be done simply by using standard web browsers like Internet Explorer, Firefox, Google Chrome, Safari, and Opera. This is because browsers are mainly designed to only view (render) HTML documents. If syntax errors exist in a web page being viewed, then a browser will attempt to display the web page in a less predictable manner (it guesses as to how it thinks the web page should be displayed). The result of browser guessing due to errors in a web page causes a web page to be displayed in a variety of fashions that are likely to vary depending on the browser and even on the version of the browser.

Often, if a web page has enough errors, it will not even display, or may display only partially. But why worry about it when you can easily check your web pages with CSE HTML Validator? Simply have HTML Validator check your web pages prior to publishing them. You may also notice that your web pages display faster and with fewer problems after syntax problems are corrected.

NOTE: CSE HTML Validator cannot check for a completely problem-free web page, although it can find many syntax errors and offer useful advice and assistance in creating your web pages.

You may also want to read the Why Validate topic.


hmtoggle_plus1What is the Cost of the Standard, Pro, and Enterprise Editions?

CSE HTML Validator Pro is free for 30 days or for the first 200 validations (whichever comes first) so that you can evaluate it. After the trial period, you must register the software if you plan to continue using it. Please see Buying Information for current pricing and other information.

The standard edition is less expensive than the professional edition but is much more powerful than the free lite edition. The enterprise edition is our premiere product and at a higher price point than the professional edition.


CSE HTML Validator is electronically distributed commercial software. You may test it free of charge in accordance with the license agreement.

You may distribute any trial version but you may NOT distribute any version that is only for registered users.

You may distribute the unmodified installation file containing the trial version of CSE HTML Validator Pro to anyone provided that no fee is charged. You may also distribute CSE HTML Validator Lite provided that no fee is charged.