I realize calling this the "definitive SEO audit checklist" likely sets me up for public mockery among my peers, I have done my best to collate tasks into logical categories. Categories are within expandable toggles below so that this page isn't ridiculously long. Each task is accompanied by a reason, and in many cases a tool that I use on a regular basis to assist me with that task.

If you have any input, additional tasks to add, reasons that require editing, tools that should be added, etc. Please don't hesitate to reach out on Twitter or by email. I would love to have this tool be something that the SEO community builds out together. Also, if you want to embed this in your site, just reach out and I'll be happy to provide everything you need.

Site Architecture SEO Checklist

Task Reason Tools
Is the site organization intuitive? Balancing User’s need to find content intuitively with need to simplify data categorization by search engines. Webmaster tools / Screaming Frog.
Does every category and subcategory have a clear purpose? Category and sub-category pages shouldn’t be considered just an aggregate of the content below but rather as a probable entry-point into the website.
Does URL Structure follow category/subcategory drilldown structure? Is content appropriately bucketed into product or service within sub-categories, and master categories?
Are key landing pages close to homepage? Placing important content close to the root is a clear indicator to search engines of the importance you place on the content.
Does site use breadcrumbs? Breadcrumbs are good for usability, but also provide “upward” links to the pages higher up in the hierarchy. Breadcrumbs are usually early in the HTML of a document, so these links are given greater weight.
Do category pages have followed links to sub-category pages? Important pages close to the root (category pages) are easy to find, and should pass links to pages lower in the structure.
Do sub-category pages have followed links to product pages? This ensures the “crawlability”, and therefore the “indexability” of lower level pages.
Do product pages within a category, and sub-category inter-link? This ensures all pages within this lowest hierarchy level pages are indexed and included in SERPS.
Is there a breadcrumb used on all pages and posts? Breadcrumbs make pages easier to crawl and index and highlight the site architecture for search engines.

Accessibility SEO Checklist

Task Reason Tools
Are URL’s Search Engine Friendly? URL’s that are not descriptive do not help. Examples on “non-friendly URL’s” are: /page-id=345 or /index.html Browser
Do URL’s use query parameters to render content? Query parameters “?” render content on the browser side, which could potentially lead to duplicate content issues.
Does all content show up in cached version of homepage? Key content could potentially not be cached by search engines. This is a quick way to find out. Cache:url
Are navigation links present in cached version? If your navigation is not present, then search engines were not able to crawl these links, meaning critical pages may not be being indexed. Cache:url
Is content being rendered using iframes or an external source? Frames cannot be indexed and attributed to the page, creating a high probability of duplicate content among other issues. Screaming Frog
How is the overall site speed performance? Site load times and site speed is a ranking factor. Google Site Speed
What are page speeds of top 10 landing pages? Use Analytics to identify top entry-pages and measure the speed of these pages. Yslow Chrome Plugin.
How does homepage speed compare to top competitors? Use the tool to create a video or visualization comparison of site load speeds Web Page Test
Are images optimized for fast page load? Images are one of the largest factors affecting page load speeds. Screaming Frog
Are JavaScript and CSS linked to external files? Loading these resources on every page slows load time down and is just lazy development.
Are JavaScript and CSS Minified to reduce load time? In addition to avoiding in line CSS and JS, compressing these files also increases page load speed. Google Closure Compiler
Is the page load speed less than 3 seconds? In general, beyond top 10 pages, are pages loading fast enough? Less than 3 seconds? Yslow
Is flash used for important elements? Older versions of flash cannot be indexed and if links exist within the file, these will not be followed links.
Do Images have ALT text? ALT Text gives the image a description and assists indexation.
Is the site returning 404 pages? 404 Pages are pages that search engines previously indexed but can no longer find. Webmaster Tools
Is the site returning soft 404 pages? Soft 404’s are pages that are not found but deliver a 200 response code instead of a redirect. Webmaster Tools
Does the site have a custom 404 page? Custom 404 pages are more likely to retain the visitor on the site than loose them.
Does the site return any 500 error pages? 500 Errors are server error pages and should be rectified quickly. Webmaster Tools
Does the site use 302 redirects properly? Pages that have moved should be 302: permanently redirected to new and current content for indexation. Screaming Frog
Does the site use 301 redirects properly? Pages that have been moved or removed temporarily should be returning a 301: temporary redirect SEOLogic Crawl Test
Does the site use AJAX Pages? An AJAX page can be indexed by implementing the windo.history.pushState() JS function
Are Headers Images? Text is preferred over images for heading elements.
Is page copy and content in images? Content should be in text not images.
Do images have a separate and dedicated XML Sitemap? Submitting an image sitemap can assist in images being indexed and showing up in image searches or keyword related SERPS.
Is the site cloaking by cookie detection? Cloaking is a violation of search engine policies. Check for cloaking by cookie with the extension. Chrome Extension
If in development, is the development server using robots.txt appropriately? Sites in development should not be allowed to be indexed.
Are there PDF’s being used on the site? Google this: site:yoursite.com filetype:pdf
Has the site been hacked? Sites that have had a history of malicious software will find it hard to be fully indexed. Keyword Spy
Is the website in a bad neighbourhood? Complete a neighbourhood check on Majestic SEO’s neighbourhood checker. Majestic SEO

Links SEO Audit Checklist

Task Reason Tools
Is the site experiencing and increase, decrease, or stagnation of back-links? The trend of back links helps content developers understand if the content they are creating is of value. Ahrefs.com
Does the site appear to be overoptimized? Signs of overoptimization include a steep backlink curve without a sustained effort, spammy links, and links from only exact match anchor text. Open Site Explorer / Majestic SEO
Ratio of links to home page versus the rest of the site? Link graph should include links to internal pages as a sign to Search Engines of quality content being created.
How does their link graph look? Link graph is becoming increasingly important in the eyes of S.E’s, understanding what they are looking for is key. How To Graph Links Blog Post
Is there a DMoz link for this site? DMoz is the original search engine, and still the only “human reviewed” directory. DMoz.org
What are the most linked to pages? Identify content of value, and more importantly content of little value that should be removed or improved. Majestic SEO Webmaster Tools
Does this site have a strong internal linking strategy? The first links to be concerned with are your own. Webmaster Tools
Does the site contain pages with too many links? Pages with too many links are considered spammy by search engines and devalued. Moz Crawl Test
Does the site contain broken links? Even one broken link can have a massive effect on the SEO value of a site. These should be rectified as quickly as possible. Screaming Frog. Status 404, 410 or 500
Are there broken links on any specific page? Broken links should be rectified as quickly as possible. Chrome Plugin
Does the site have an XML sitemap? XML sitemaps are different to HTML sitemaps in that they are specifically for search engines
Does the site have an HTML User Sitemap? In addition to search engine sitemaps, including a well formatted HTML version for humans helps with accessibility.
What is the quality of the outbound links? If a site is linking to a number of low quality websites, the quality of the site
Are internal pages competing for the same organic terms as main pages? Evaluate the anchor text used to link to internal pages and compare to what pages are ranking for those terms. Webmaster Tools
Do pages contain internal links using anchor text as the link to appropriate internal content? Anchor text internal linking from body content is a primary accessibility and crawlability issue
Does the site have a resource / directory / links page that serves primarily as a link exchange? Low value links were the specific target of the Penguin update, and no doubt included in the Hummingbird update.

On-Page SEO Audit Checklist

Task Reason Tools
Are images SEO Optimized? Images should be named using the keyword target of that page; it should reside on a permanent URL that contains the keyword for that page and have an appropriate ALT tag and Title. Screaming Frog
Are their images being indexed? Take the name of the image and do a search in Google image search.
Are there any page titles longer than 70 characters? Titles longer than this may not show up in search engine results pages.
Are Meta Descriptions limited to 155 characters? Descriptions longer than this may not show up in SERPs
Are Page Titles optimized? Do they contain target keywords?
Do Meta Descriptions contain calls to action? CTA’s encourage a click from a SERP.
Are any pages missing Titles or Descriptions? SEO 101.
Does each page contain an <h1> heading? Headings are important to users and Search Engines.
What is the quality of calls to action? Evaluate top level pages to ensure it is clear what the user is intended to so.
Does the site have ads? Ads have repeatedly been identified as decreasing user enjoyment of a page and should be avoided above the fold, and especially avoided if they are not relevant to site content.
Does it appear that the site is attempting to stuff keywords? Keywords should be used judiciously and within the guidelines of search engines only. Moz On Page Grader
Is there a “related posts” section at the end of each page? Related blog posts can add colour, invite users to continue reading, increase engagement, and position this site as an authority.

Keyword SEO Checklist

Task Reason Tools
Has the webmaster been tracking keywords? Historical data is extremely valuable
If so, are there any keywords missing? There is no substitution for doing your own keyword research and comparing your results to what is being tracked.
Are keywords well organized by category? Was the way the site was setup to target organic traffic make sense? Google Analytics
How does this site’s rankings compare to competition? Gaining competitive insight is often the best place to start for what they wish to rank for. SEMRush, Webmaster Toos. GA.
Does this site have multiple pages ranking for the same keywords? Pages should be organized to target only one search phase per page, a “site:yourdomain.com keyword” search will answer this question. Google
Does homepage show up for branded search keywords? If not, they may be experiencing a manual penalty.
Does the site offer a site search? If so, are they tracking the site search in Analytics? This will highlight opportunities to create content your users want. Google Analytics
Is this site engaged in PPC? If so, does their keyword strategy maximize value? This analysis requires an experienced touch to identify opportunities to improve Adwords, MS Ad Center.

Google Analytics Audit Checklist

Task Reason Tools
Which direction is the trend? Up or down? Is the site gaining new unique visitors or losing them at a steady pace?
How is this site tracking traffic? What analytics system are they using?
Is this website tracking conversions and events? Conversion tracking will often give you insight into exactly what the intention of the website it, if there is no way to track something, then there is no clear goal of a website.
Is the analytics tracking code missing from any pages? The accuracy of any analytics tool is based on the quality of the data it receives. If there are holes in the data, there will be holes in the analysis.
Do other sites have the same GA code? Simple confusion in User Account details can cause tracking mistakes. GA/ technology / network / hostname
Does the site have subdomains being indexed? Subdomains are sometimes development platforms that can cause duplicate content issues if not cleaned out. Search: “site:yourdomain.com –inurl:www”
Are PPC landing pages showing up in Organic Search? Often PPC landing pages are intended for a specific audience and should be limited from indexation. GA / traffic sources / sources / search / Organic / landing pages
Is this site tracking site search? As noted in content, tracking site search helps highlight content gaps.
Is the site search effective? If you conduct a few relevant searches, do you find the content you are looking for?
Does the site use the Asynchronous tracking code? Older versions of the code can cause problems. Also the asynch code allows for webmaster tools verification etc.
If the site homepage contains something like “/index.html” has the default home page been set in GA? Admin / profile / profile settings / general information / default page.
If using Adwords, has it been linked to the analytics account? Linking these accounts provides valuable insight across platforms.
If using Adsense, has it been linked to the analytics account? Linking these accounts provides valuable insight across platforms.
Are UTM parameters being used appropriately? UTM trackers provide additional information to GA for reporting purposes. GA URL Builder.
Are events being tracked properly? Events can vary from scroll, to video plays, to “mailto” clicks. Determine what you want to track and use click events to track that.
Is the Remarketing analytics tag being used? The Analytics Remarketing tag offers more flexibility than the Adwords option alone.

International SEO Audit Checklist

Task Reason Tools
Is the site Language oriented or Geographic oriented? If language oriented then a “youdomain.com/es/” is the best solution. If geographically oriented then the local top level domain (TLD) is the preferred method.
Is content optimized for local use? For example, a site an a site.eu TLD should be quoting prices in Euro, not Dollars.
Does the URL structure match the language? In the “.com/es/” example, the categories, sub-categories, and product pages should have Spanish URL titles.
If the site is targeted to a specific country, is that indicated in Webmaster Tools? In addition to the TLD being localized, ensure search engines are aware of the localization of content in WMT.
If the site is targeting a specific country, does it have a local IP? Verify that the site has a local IP using the Server Stats tab on domaintools. Domain Tools
Does the sitemap include the “rel=alternate” hreflang=”x” annotations? These references help search engines understand that you are aware these pages may have similar content and it is in another language. Google explanation of markup.
Does the Robots.txt file include reference to the language sitemaps? Help search engines to find the sitemaps for the alternative languages.
Is the language of the international pages content specified in HTML doctype declaration? The language of the content should be specified as described in w3.org documentation.
Is the site targeting multiple countries with the same language? (eg. Domain.com/au and domain.co.uk If a site is targeting multiple countries speaking the same language with its own domain, then the content on each one should be unique.
Does each version of the site and languages permanently link to each other? Gives users and search engines a way to find all the international versions of the site and ensures they are crawlable.
Does the site suggest content in the appropriate language version by language and location? Detecting the users default browser language can help identify the language of choice regardless of their location and allows you to make suggestions for appropriate content.
Does the site have localized content and links to local resources? For example: A world map in the UK is different to a world map in the US, and UK locations on the UK site and vice versa.

Semantic Markup SEO Checklist

Task Reason Tools
Is the site using structured markup? Schema.org, facebook open graph, microformats.org, XFN Webmaster Tools
Does the site use rich snippet content? Videos, Reviews, Ratings, Recipe’s, Author, Event, Product, Offer, etc? Schema.org
Is the markup validated? Markup obviously is only of value if it meets markup standards for validation. Google’s Validator and FB Tools Debug
Does the site need microdata for local business? Microdata was a pre-cursor to schema, but still valuable for indicating location settings for a business. Microdata Generator
Are competitors using structured markup? Use the Sindice tool to search for your target keywords, only sites using structured data will display results. Sindice.com
Do the rich snippets follow Google’s guidelines? Consult the guideline page for tips in implementing structured data, and troubleshooting. Google Guidelines.
Does the site have schema on reviews? Schemafied reviews will display the number of stars right in the search results. Schema Creator

Video SEO Checklist

Task Reason Tools
Search YouTube for a branded channel for company videos. A brand channel allows for added control of how videos are displayed and consumed and is the preferred YouTube channel
Do videos contain schema.org rich snippets on all videos? Schema snippets aid search engines in understanding the video and its content Webmaster Tools
Have all videos been submitted to Webmaster Tools by way of an xml video sitemap? Video sitemaps, regardless of where the video is hosted, will assist in the indexation and content accreditation.
If video sitemaps have been submitted, are all videos indexed? Search engines may choose to not index a video for many reasons, but the first step is identifying which ones have and have not been indexed.
Is the video sitemap formatted correctly? Video sitemaps differ from regular sitemaps and require different formatting.
Do all videos reside on one page? This is not ideal. Ideally, videos reside on their own page with text (possibly a video transcription).
If videos are embedded, have they been transcribed? Video transcription in conjunction with a video sitemap can assist in proper video content accreditation and indexation.
No matter the site’s choice for video hosting (YouTube, Wistia, or self hosted) are all videos available on the platform of choice? Spreading videos across platforms can cause confusion for users and duplicate content concerns for search engines.
Do all videos contain optimized Titles and Descriptions? Like any page, search optimization is key to its success, and as much effort should go into video titles and descriptions as the content of the actual video
Does the video contain a call to action annotation to comment or share the video? As with any content, users want clear direction on what you expect them to do next, depending on the intention of the video, tell them what to do next.
Do the annotations include links to other videos from the site? It stands to reason, if someone is enjoying this content, they may enjoy other, related content.
Are the videos receiving favourites and likes? The most rudimentary measure of success for a video is the audience reaction, and YouTube has offered a thumbs up and down since the beginning of its service.
Are videos published regularly? Is there a publishing schedule? Like with all SEO efforts, search engines want to see a serious sustained effort rather than peaks and valleys.
Do video descriptions contain a link at the beginning of the description? Linking to the on-site version of the content will encourage comments and user engagement in your videos.
Do videos have a clear intent? Promotional videos are promotional, and product videos not overly promotional?
Have automatic closed captions been updated to accurate ones in the actual language of the video? YouTube will automatically add CC’s, but most often these are off, or even potentially embarrassing. Ensure these are correct so that your message is clearly understood.
Are social share buttons readily accessible while watching video content? Possibly the number one use of video content is the small chance that it can be shared thousands of times. Make it easy for your users to do so.
Do videos have CNAME aliases? This counts as a second link: one for to reference the video file and second attribution to a page of your choice.

Design And Branding SEO Checklist

Task Reason Tools
Has the site conducted a clear co-citation link strategy and claimed local pages? If the site needs a local presence, it is important to claim all local directory and citation source pages. Visit GetListed for existing links, and local visibility to find sources GetListed.org and Local Visibility
If the business is a local business, do they list a local phone number? Local phone numbers increase conversion as the sub-context message is: local company
If the business is a national business, do they list a national or toll free number? Toll free numbers are very powerful when indicated so, less powerful than they used to be, but still important.
If the business has multiple locations, does the site have a page for each location? Each page should be separated geographically, optimized accordingly and submitted to Webmaster Tools as well as Google Places. See the attached link for multiple listing templates. Places Multiple Listing Template
Are all business details correct in Google, Apple and Bing Maps? People often forget about Apple and Bing Maps, but many larger websites opt for these as embed sources to save money. Submit updates to Google through mapmaker link. Mapmaker
Are existing listing in reputable web directories and business directories? Quality links are more important than volume of links. Lingering links from historical over optimization campaigns can harm site presence and value to search engines. Open Site Explorer
Does the website have a clear growth strategy including (if applicable) an affiliate program? Does the site know how it intends to grow, gain new clients and stay current with web trends?
Has the site conducted any noticeable conversion optimization process? Has any effort been put into converting the traffic the site is already getting? Check for crazyegg, optimizely tags
What CMS does this site use? Every CMS has its pros and cons. Carefully selecting the appropriate CMS for each site can have far reaching and long lasting repercussions
Does the site use a favicon? If there is no favicon present, browsers, bookmarks and even certain PPC opportunities will simply display a white box, a branding opportunity missed.
Does the site offer site search? Site search is a proven user-friendly tool to offer quick access to content that users want
Is site search in the top right corner of each page? This has been tested and proven to be the location users immediately look for: 1. A phone number and 2. A site search field.
Describe the user experience for the home page? User experience will determine engagement, retention, bounce rate, page views etc. The online world is essentially ADD. You have an instant to grab and retain attention.
What is the user experience on category pages? Users expect category pages to be the conduit to finding products and services quickly and clearly without ambiguity.
What is the user experience on research type pages? Has the content team crafted a clear research friendly content strategy targeting the “Who”, “Where”, “What”, “When”, “How” Searches?
What is the user experience on conversion centric pages? Product pages should offer tools to research the product, compare to competitors and similar products and offer related products and services.
Does the site obviously use stock images? Sometimes called “smiling heads” look generic and offer no value to a site.
Are problem pages easily identified? GA report template to the right sorts organic landing pages by bounce and exit rates. GA Custom Report
Are any videos on the site set to autoplay? Autoplay has repeatedly proven to be a negative user experience that users don’t have control over and don’t appreciate.
Does every page contain a logo in the header? It is a simple best practice to include a header logo linked to the canonical version of the home page.
Does the site have an “About” page. This is often the “go-to” page for users seeking compelling information about the website content publisher.
Does the site have a Contact page that is easily found? Contact us pages should be easily accessible and informative with mailing address, map locations, and telephone numbers.
Does the site have sitelinks for branded search? Search the brand name of the website, does the SERP have multiple link display to the main categories of the site?
Are competitors bidding on branded terms? Searching the terms may not be the best way to identify this due to the location of the search. SEMRush or other tools may be better suited to more accurate results.
Does this site have reputation management issues? Include the word “review” or “reviews” along with primary branded terms in a search and analyze results.
If there have been historical negative reviews, has the company responded appropriately? Look for offers of compensation, and conciliatory tone in responses from the company.
Does the business get regular mentions on other blogs? Try a blog search including branded phrases, or comb through OSE results for blog mentions.
Does the business conduct any charitable events? Do charity sponsors inter-link?
Does the business engage with industry associations? Do these associations have profile pages? If so, is the content accurate and can the page link to the corporate website?

The Social Media SEO Checklist

Task Reason Tools
Do content publishers for this site conduct a social campaign? If so, what networks are they using and why?
What is the quality of social interaction? Overly commercial? One way? Interactive?
How many social mentions have their top organic landing pages had? Open site explorer can give you a broad overview of the number of Twitter shares, Facebook likes, and G+ “+1’s” a page has.
Are links being appropriately tagged for tracking purposes? Tagging links allows proper measurement of off-site engagement strategies. Look for URL amendments including “utm_medium”, “utm_source”, and “utm_campaign” etc.
Are email marketing efforts being tagged for measurement and tracking purposes? When mining data in Analytics under traffic sources/sources/referrals, if email is not showing up, then tracking is not working.
What have their last two weeks of tweets looked like? Backtweets is a Mozbar tool that allows you to see the last two weeks of tweets.
Do content pages have social buttons? Quality content is usually a site’s most share-worthy resource, make it easy for users to share and mention online.
Can visitors easily leave comments and subscribe to comments? Encourage sharing without making anonymous sharing available as this often backfires.
Does the site make it easy to log in to leave a comment? Do they allow Facebook comments? Twitter login? Disqus?
Does the site us a social plugin that allows comments to be tracked? The plugins “ShareThis” and “AddThis” connect directly to GA for tracking purposes.
Is the site using Pinterest, Instagram, Vine, and other social sites effectively? Depending on site goals and target audience, Facebook may not be the best social media platform and consideration may be given to other sites with differing demographics and behaviours.

A big shout out to Annie Cushing for providing the framework or wireframe, and inspiration for this post. Props.

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