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Day#26: Markup Validation Service – is your HTML valid?

I was introduced to this tool in my web development class and used to get annoyed with it, especially when my HTML page works fine and shows all the elements it’s supposed to. But  I learned later on that it’s an important stage for building a complete and proper webpage.  

Markup Validation Service or Markup Validator helps validate an HTML page. It’s a free tool by W3C (World Wide Web Consortium). You can use it by pasting the URI of the page, uploading file, or even directly pasting the markup language of the whole page into the tool’s input area like below.

Image: Markup Validation Service page - direct input area
Markup Validation Service – direct input area

Why is it necessary to validate your HTML page?

  • It helps debug the page – like a debugging tool. It helps identify what you miss on your page by highlighting and locating the errors. Maybe you forget a closing tag or have an excess tag that shouldn’t be there. 
  • It helps set the page up to web standards – let me refer to its documentation: “Validation is one of the simplest ways to check whether a page is built in accordance with Web standards, and provides one of the most reliable guarantee that future Web platforms will handle it as designed.”
  • It helps train good practice – your page may work just fine without fixing any small HTML errors, but having a habit to correct the errors or try your best to solve them is a good habit to have. It’ll train you to pay attention to details, which is a fundamental skill that could prepare you to work with a more complex coding project. 

Do you use Markup Validation Service? How does it help you in your coding journey?


This is day#26 post and a part of my commitment to spend 30 minutes a day for 30 days straight to write about software development tools that I love. My goal is to build my daily writing habit and connect to more people. This project is inspired by @dickiebush ’s “Ship 30 for 30” Atomic Essays. 

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