Valid Source Code Helps SEO?

I just read an interesting article at Search Engine Journal claiming valid source code helps spiders better index your site. I’ve known about the importance of validating, but I had no idea it affected how your site was indexed.

What is Validation?

According to the W3C:

Validation is a process of checking your documents against a formal Standard, such as those published by the World Wide Web Consortium (W3C) for HTML and XML-derived Web document types, or by the WapForum for WML, etc. It serves a similar purpose to spell checking and proofreading for grammar and syntax, but is much more precise and reliable than any of those processes because it is dealing with precisely-specified machine languages, not with nebulously-defined human natural language.

The article gives a few tips including:

  • Use W3C to make sure your site is viewable in major browsers, especially Firefox & Safari
  • Test your site on mobile browsers
  • Check for all errors in HTML coding and fix them when possible

If you are interested in learning about the benefits of valid source code and how it could help SEO, then read SEO & Importance of Valid Source Code.

26 thoughts on “Valid Source Code Helps SEO?”

    1. Sure. Make sure it’s valid as xHTML Transitional plus check if it’s readable when CSS is turned off.
      Firefox has a feature to turn off CSS: Menu->View->Page Style -> No Style.

      If it looks ugly and unreadable without CSS, then you need to work on the site’s layout…

  1. Good article. In a lot of cases if you are working with XHTML and CSS anyway making your code standards compliant can sometimes be quite simple. Even just changing things like the ampersand (&) to & in your code, or closing image tags with /> rather than > can make all the difference.

    1. Just because their site doesn’t validate does not mean they are not a trustworthy source. I have actually read a lot of good material at Search Engine Journal. Even Google’s homepage does not validate. It is actually pretty rare when a site is perfectly XHTML valid. Nonetheless, they raise some interesting points as does John Lampard about how pages determine content vs. code when there are tags left open and other inconsistencies in the source code.

      1. Let’s say there is a batch of tags that you have to use correctly. But definitely it doesn’t means that your page must be valid to be ok with Google, right?

  2. I think that it’s a little unfair to penalise sites for sloppy code, if this is indeed the case. The web should be about the ability to publish and have a voice. When only a small percentage of site owners are coders then it disadvantages everyone else. I believe compliance is a good thing that everyone should strive for but to negatively impact your SERPS for non-compliance is a bit harsh.

  3. I have a few sites that are 100% valid xHTML, didn’t notice any improvement in SERPs. I still think it’s good practice, “Leave no rock unturned”

  4. Valid code is good in that one may avoid a lot of layout/formatting bugs that could otherwise creep into a design. But saying that valid code helps SEO is really oversimplifying things. As another commenter noted, Google’s own home page doesn’t even validate.

    One thing that DOES help SEO is using external CSS and JS files instead of cramming it all into your HTML files. This increases your keyword density because Google makes no distinction between actual text, HTML formatting, CSS, JS, or anything else. This is also better from a maintenance and performance standpoint, so it’s good all around.

  5. Validating is an important thing, whether we like it or not – but I’ve known a few sites that look differently in different browsers although they are validated, so I guess validation doesn’t catch everything.

  6. I have paid more attention lately to a cleaner code and I think this can help me more. by coding myself the layouts and working on the SEO as I type I do give myself more chances to actually increase my sites’ chances for a better place in the searches and some more traffic.

  7. Reading the original post I got worried but then I read the comments and saw how a site doesn’t have to be validated to get good rankings. This is good to know as my site doesn’t have valid XHTML at the moment.

  8. I agree it may be a minimal quality score factor but nothing beyond minimal. If you are optimizing a site and look at ROI on time spent this one should be at the bottom of the list.

  9. agree it may be a minimal quality score factor but nothing beyond minimal. If you are optimizing a site and look at ROI on time spent this one should be at the bottom of the list

  10. I once bumped into a site where it shows you how your site looks on other browsers. My site looks good on Firefox, IE and Chrome, does this source codes affects the layout?

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