SEO & Importance of Valid Source Code (W3C Validation)

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Does W3C compliance impact a site’s search rankings? The question has been mulled on Search Engine Journal in the past and the basic conclusion is that although W3C is incredibly important for browser compatibility and overall site usability, it does not have a direct impact on Google rankings, especially since Google’s pages themselves do not validate.

However, it is still a common practice to make sure one’s pages do validate W3C standards, and in the future, in an effort to judge site authority and quality, Google may just include W3C validity in their algorithm; you never know.

Besides, believe it or not, there is much more to the web than only Google. And Yahoo, & MSN’s Live Search are also major traffic generators in the Global search market.

Additionally, if you’re going to be running a social media campaign, planning on running a story on Digg, and the majority of Digg users use a browser such as Safari or Firefox which your site may not load correctly in or results in botched CSS formatting, your story is going to get no attention and you’ll be missing out on the potential of hundreds of organic editorial links.

So, when looking at the whole picture; presentation is reality is reputation… and having a smooth and valid site is critical to your company’s reputation.

Mike Tekula of New Sun Graphics sent Search Engine Journal a write-up of the importance of valid source code and SEO and here are some of his tips in assuring the search engines can properly read your site’s coding and browser compatibility. Enjoy.

    Testing your web pages in browsers is an absolutely necessary process for building any web page. It allows you to see what others can see, and often you will notice mistakes in your HTML code because of the symptoms they cause in browsers. But what about when your testing browser(s) display the pages exactly as you intended. Are your pages error-free? Not necessarily.

    The World Wide Web Consortium (W3C) sets the standards for coding HTML and CSS for web pages. They also provide tools to validate your code for free. So do some third-parties. The question you might be asking is, “if my page looks fine in Internet Exporer, Safari, Firefox, etc. why do I need to worry about validation?” If all you’re looking is for proper display, you might not have to. However, if you’re concerned at all with search engine optimization (SEO), and you probably should be, validating your source code is a necessity.

    One reason for this is the difference between search engine spiders and browsers. Spiders “crawl” the web indexing web pages and their content. They are basically toned-down web browsers that aren’t concerned with displaying for a user but with recognizing content. In other words, search engine spiders are looking at the same code your web browser is and parsing it in a very similar way. This difference in functionality, however, is vast.

    There is a very real pressure on web browser developers to ensure that their browsers display pages correctly to the user. This often includes forgiving errors in the source code. Improperly nested elements, unclosed tags, unrecognized parameters – these are all errors in HTML code that might not affect your web page’s display in your favorite browser. When it comes to search engine spiders, however, it can be an entirely different story.

    That is not to say that small errors in your HTML code will spell death for your search engine rankings. Certainly they won’t normally make your page invisible to spiders.

    They can, however, disrupt the vastly important process of a spider parsing your page for all relevant content or make some of that content invisible. And since so much of SEO is paying close attention to every little detail of your site and its content, why leave the possibility open of causing problems for search engines when they try to index your pages?

    Validation might mean some big headaches when you set out to fix every last error on your pages, but the benefits of valid code are clear – and running your pages through a validation service like that of the W3C can do a lot in the way of educating you about the mistakes you may be making.

So, in a nutshell, here are some basic tips:

  • 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
  • Pay attention to your programming errors and be aware of them when programming your next site
  • If you pay for a designer, put something in the contract that the site must pass W3C validation.
Loren Baker
Loren Baker is the Founder of SEJ, an Advisor at Alpha Brand Media and runs Foundation Digital, a digital marketing strategy & development agency.
Loren Baker
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  • Michael Martinez

    This is absolute nonsense. HTML validation has absolutely nothing to do with establishing relevance. The search engines will judge “quality” on the basis of popularity and precedence of relevant content (as determined by user queries).

    One might as well argue that using JPEG images is better for search than using TIFF images for some obscure technical prejudice.

    The W3C may be striving to accomplish very worthwhile goals, but the facts remain that most people create Web content without any knowledge of the standards recommendations made by the W3C, toolmakers implement features and behaviors that go beyond the W3C recommendations, and search engines just have to deal with the Web as it is, not as W3C compliance advocates want it to be.

    W3C compliance should be implemented for the users, to improve accessibility and usability, and that’s it. There is no compelling reason for any search engine to ever score relevance on the basis of HTML coding styles.

  • Robert Wyatt

    Wow, sounds like someone doesn’t follow recommendations and therefore thinks that no one else ought to!
    Are there valid statistics for what “most people” do?

  • Michael Martinez

    Robert Wyatt asked: “Are there valid statistics for what ‘most people’ do?”

    You mean like these?

    They examined 1,000,000,000 pages. How many have you looked at?

  • Robert Wyatt

    1) That page lists occurrences of W3C-approved tags; it doesn’t list percentages of compliance, nor does it list what most people have knowledge of.
    2) That page uses SVG and suggests use of one particular browser (Firefox 1.5) because it is otherwise unusable.
    3) How many pages have I looked at? Well, I’ve looked at your page and found over 60 errors starting with the fact that it had no doctype.

    Now, whether this has anything to do with search engines I couldn’t say, but I also don’t see how you could.

    Take care,

  • Michael Martinez

    You obviously didn’t read through the entire study, which examines a large number of non-standard uses and explains why Google doesn’t require compliance and cannot require compliance in determining which pages are most relevant to user queries.

    Your condescending tone is actually quite typical of compliance advocates who clearly haven’t grasped the fundamental principles of search indexing technology. It’s not the code that matters; it’s the content.

    I don’t have time to monitor this discussion further today.

    As far as my Web site goes, it renders. That’s all I care about. W3C recommendations cannot transform the realities of the Web. Anyone who wants to be a compliance snob is certainly welcome to be.

    But W3C compliance has absolutely no impact on SEO.

  • Robert Wyatt

    I’m sorry you felt I was condescending in advocating standards. I feel like your argument is akin to telling my boss that it doesn’t matter what time I get to meetings, only whether the meeting took place. The analogy refers to time zone standards and whether realities conform to them or vice-versa. Around here we’d say you’re all hat and no cattle. I’d guess I’m also a timezone snob in your book. I’m okay with that.

  • Gary T

    I agree that compliance to these standards is important, but look at the hard work involved for not very impressive returns. Most pages (if or not they comply with the standards) display properly in firefox and IE which are the most popular browsers, unless the coding is real crap. SEs don’t place importance on these standards. Very less motivation for me to adapt to these standards which involves extra work.

  • Gerard McGarry

    I’ve always understood web standards to be good for SEO because they improve crawlability, remove extraneous code and make the page easier to index.

    Plus, I remember reading somewhere that this tied into Google’s mission to make the world’s information accessible to all.

    However, I find it hard to believe that search engine spiders haven’t evolved to the point where they can ignore the odd un-nested tag or a bit of invalid code. The spiders are (literally) at the forefront of search – it’s hard to believe search engines don’t spend as much time developing them as they do their algorithims.

  • Jaan Kanellis

    Validating makes sense to do, but doesnt have an effect on ranking a web page. If Google demoted websites that had invalid code the web would be a very, very, very different looking animal.

  • Relocation

    I agree with Jaan Kanellis. Search engines need some time to support it.

  • Ricardo

    I think standards are the way to do “good” and correct things, and people who want to accomplish with them are looking for that. Spiders or not, the web must be a built as a better place for everyone.

  • David Wolf

    While compliance is not required, it deserves a bonus. Our algorithms reward a well-coded and meta-rich document much more than trash produced by children using frontpage.

    High source code quality IS correlated to strong ranking, but perhaps not causal and only a symptom of effective internet operations.

  • Albert

    At least, this affects to a certain degree, because if your website is well programmed, you’ll get receive more visitors (multi-browsers sites!). It HAS to impact -for good- somehow.

  • Josh

    Ha the pages for this website and Mike Tekula of New Sun Graphics, which “…sent Search Engine Journal a write-up of the importance of valid source code and SEO..” dont validate..
    BOTH OF THESE PAGES DONT VALIDATE and they’re talking about how it’s important to have valid pages for SEO. Almost as funny as the nerds having heated arguments through comments about some useless google study.

  • Tom

    The Web sites must be always validated against W3C standards regardless of the SEO effect, because such sort of programming style indicates about the professional approach used in the Web design company and skills of the team in particular. The output generated will look greater in all browsers and this benefits the end users as well.

  • Clark Smith

    Great Article, My website doesn’t rank the best for w3c Validation but i’m ranking #1 for my main keywords. Where are some low costing companies that can fix these errors without changing the appearence of the site? Thanks!

  • Dual Diagnosis

    Mine has about 22 errors but is ranking better than sites that DO validate, I don’t really belive it matters.

  • Rick Duncan

    Validation doesn’t have a direct effect on relevance but removing that excess code increases the text to code ratio so whatever the page is relevant to just becomes more relevant …. onsite optimisation is only half the story though, external links coupled with onsite optimisation is where it’s really at.

    Having your site validate is more about giving yourself a warm feeling inside knowing that you’ve done the job to the best level that you can, and it’s usually those type of people that ‘tend’ to do better at what they’re trying do achieve including SEO!!


    thanks to you all…
    but can anyone tell me what should be the important things we have to consider during coding. By which all pages will be w3c validated…

    thanks in advance….

  • Jarvis

    I agree, I think for now W3C Validation is only best so that everyone can view your site and not certain browsers. Maybe in the future it will be beneficial for SEO.

  • Dr. Spinner Dentist

    A good way to create easy websites that all validated is with wordpress. Takes less than 5 minutes to install and you can change the template or theme with a click of a button!

  • Keith Pearson

    The trouble with the anti-validation argument is that is really is rather short-sighted.

    Just as link-building has become the holy-grail for SEO, none of us know where the search engines will take us next. From my point of view as a website Designer, I’d rather be in a position where every site I’ve build is fully validated so I don’t get caught ‘if’ validation ever became more important with search engine ranking.

  • Jay

    I have consistently seen websites that follow no standards whatsoever appear at the top of google search results. When a validation on these sites are done using the W3 validator they reveal countless warnings and errors. Many of these sites even use tables in place of divs for layout. Many also use keyword stuffing and none of these things appear to adversely impact their ranking.

    This makes me wonder how many SEO commandments by supposes gurus are correct and how many are just baseless theoretics.

  • OC Marketing

    I have also seen websites that rank Very well in Google which have so many errors and you can’t even view the sites in Safari or Firefox…

  • Judy

    Great article – thanks! It is so important for people to do their homework when choosing Website Designing related Topics. If you’re interested in purchasing Domains and etc , checkout the site with all related great information’s..


    Thanks! I think that validating is a smart thing to do! You want to make sure your site works before you start syndication and importing your work.

  • Guaranteed Seo Services

    W3C validation is definitely important. When you’re doing W3C validation it is not just improving the download speeds of the net, it also advise you on the errors. To those who think it is not important, I’ve seen my client’s websites shoot up to the rankings that they were initially meant for.

    If you think it’s not important, register a Google Webmaster Tool account and you will see Google pointing all those errors you have. Broken links is just a small error you might think but it does affect your site ranking.

  • Peters

    If Google’s goal is to take care of user experience, they should take this in consideraton, as they seem to take in consideration the speed of the site now.
    I realise google does not use information like provided by alexa ( time spent on the site, average page per user ) that’s what make me think that google can improve their results and user experience a lot, and if google does not do that, someone else will do that. Remmeber that Altavista was THE search engine, no one would have predict that they would disappear from the landscape.
    Make good valid website is important, and does not take so many time of work as one wrote it just above. 2 hours and you can check your errors. I fell from 130 erros to 0 on the homepage

  • Andrew

    It appears that SE ranking doesn’t account for validation so what you do now may not be that important, however I see plenty of reasons how W3C validation could have something to do with page relevance when performing a search.

    Say I am a Mac Safari user searching for nuclear physics websites. Google will return a number of results in the order of calculated relevance for that particular wording I used. However, considering valid code, why would an invalid site polluted by (for example) IE specific css, obsolete tags, etc which have a fair chance of making the content unreadable for me, be considered relevant for me? The SE has all the information pertaining to the client app I am using, therefore it could (and should) filter out (and consequently disconsider) results that would not work for me.

  • Industrial Photography

    This is an interesting blog. The articles about SEO is really good. Thanks for sharing.

  • Corporate Photography

    Interesting. Never realised that SEO was so important.

  • Studio Photography Singapore

    My partner directed me to your site. This is really a good resource page.

  • Photography Services Singapore

    Appreciate the sharing. This is still very new to me.

  • Industrial Photography

    This is an interesting blog. The articles about SEO is really good. Thanks for sharing.

  • Corporate Photography

    Interesting. Never realised that SEO was so important.

  • Studio Photography Singapore

    My partner directed me to your site. This is really a good resource page.

  • Photography Services Singapore

    Appreciate the sharing. This is still very new to me.

  • Guy Manningham

    Thanks for clearing this up. Some of the errors and warnings that come back from the HTML validator will negatively impact SEO, such as missing alt tags on images. Just some food for thought.