When we developed our new GeekWire website in September, one of the critical steps in the process was to run each page template through a few diagnostic tools to make sure that our code was correct. Whenever we make a change or develop a new section or page, we are sure to pass the new pages through these tools to make sure that our pages are displaying valid HTML, structured data and social media tags.
We have tens of thousands of pages on our site, so clearly we can’t physically test every one. In fact, with a template-based website like WordPress or any other CMS, you really only need to test one page from each template. Check the home page, check the archives page, check the single article page, etc.
W3C Markup Validation Service
The W3C is the consortium responsible for web standards, and they offer a nifty tool to check the validity of your markup against the HTML, XHTML and other standards. Web browsers are quite tolerant of many sorts of errors that don’t fit the W3C specs, but the validation service is quite strict. You’ll receive errors on just about any page that frequently cause no rendering issues in browsers. Some of them are clearly coding mistakes for you to correct. Other times there are tags used that aren’t registered, or maybe an embed code that is still using some obsolete tags. They key here is to sift through and fix the obvious errors.
Unlike the tolerant web browsers, RSS feed readers don’t like invalid feeds. The other tool we use whenever we change the structure of our RSS fee is their feed validator. This will check to make sure that your feed conforms to RSS standards, which is essential to making your feeds work with external services.
Google Structured Data Testing Tool
If you want your pages to appear nicely in Google, it helps to add structured data markup to better describe the structure and content of your site to them. This data is added to a webpage using the schema.org vocabulary, using either the microdata or JSON-LD format.
The Structured Data Testing Tool will show you all of the metadata that Google can find on the page and will also list off any errors. Depending on the sort of metadata, you may also be able to preview how your page will appear in search results.
Bing Markup Validator
Bing Webmaster Tools also has some useful tools to validate your markup or analyze whether a page follows SEO best practices.
Facebook URL Debugger
If you want your webpage to appear nicely when it is shared on Facebook, you need to add certain Open Graph tags to the page that identify things like the title, description and image. To test if Facebook has what it needs, run the page through the Facebook URL Debugger.