SEO Audit

What is SEO?

SEO stands for Search Engine Optimization. It’s the practice of optimizing the ranking of a web page for relevant keywords on different search engines such as Google, Bing or Yandex. Millions of blog posts and new pages are published every single day. It’s of utmost importance to master this process in order to stay on top of your competitors and bring free high-quality traffic to your website all year long.

SEO can be conceived in two categories. On-Page SEO concerns the optimization of the page itself (structure, metadata, performance…) and its content (quality, keywords, links…). Off-Page SEO is meant to improve external factors that affect its ranking just like backlinks or associated social media profiles.

Search Engine Optimization generally involves a significant time investment and acute knowledge on how the Web - and search engines - work. We usually need to wait several months before reaping the benefits of an enhanced page.

However, it is entirely worth it as it ensures a long-term recurring flow of highly engaged visitors on your website for FREE. Ensure that your pages reach high visibility on popular search engines via this low-cost strategy. It is extremely rewarding converting this initial time and SEO efforts into free organic traffic in the long-run.

This practice is highly contrasted with SEM (Search Engine Marketing) where you need to pay a search engine in order for your page to be positioned on top of the search results. Even if SEM provides nearly-instant and qualified traffic to your pages, it is a much riskier strategy as it implies initial money investment (displaying ads) and does not guarantee positive returns.

Perform a free SEO audit over 70+ criteria

Search engine algorithms and rankings are evolving daily. For example, Google constantly tunes the ranking of web pages for specific keywords to continuously enhance its search results for each user, depending on the search query, location, context, device and many more attributes. No one fully understands how search results are sorted against each other as this is now mostly dictated by artificial intelligence and the secret sauce of each search engine.

However, mother companies like Microsoft or Google regularly update the community regarding most guidelines and factors they take into account when computing search results position. Every 6 months or so, you can expect a big update from most search engines that may significantly affect your rankings and free organic traffic towards your website.

Fortunately, we got you covered! On this page, you can run a completely free On-Page SEO Audit on any web page in under one minute. We’ll ask our best robots to crawl your page, analyze it against more than 70 factors and provide a detailed SEO report combined with a global score (out of 100). This helps you quickly assess what you should improve on that page and make it much more visible in search engines results.

We recommend you to bookmark it and run this SEO audit after each code or configuration change you apply to your website. That’s how you can stay on top of your competitors and get the most out of search engines’ free organic traffic.


In under a minute, our robots will analyze relevant properties of the specified web page and give you unique insights on what’s great about it and what could be fixed. This assists you in improving its search engine rankings and boosts its free organic traffic. Let’s deep dive into what we scrutinize for you.

> Global score

Over all the attributes detailed below, we compute a global SEO score for that page. This helps you quickly understand the general SEO performance of a page and its evolution between audits.

> General page information

Our crawler retrieves and displays fundamental properties of a page. We check the following attributes:

  • Crawlable: In order to show a page in search engine results, make sure not to provide any noindex HTTP header or meta tag which would prevent it from being indexed from their bots.
  • Its domain provides a valid robots.txt: Publish a robots.txt file at the root of your domain name and make sure it’s valid.
  • Has a valid hreflang configuration: Use valid language in ISO 639-1 format as the hreflang value when linking a document to its variant in a different language.
  • Doesn’t use any plugin: Search engine crawlers generally do not parse and index content based on browser plugins like Flash or Java.
  • HTTP status: Verify that the page returns expected HTTP status code.
  • Tap targets are correctly sized: Take care of correctly sizing and spacing the UI elements which you expect users to interact with. This makes for a smooth user experience on any device.
  • Document response time: The document’s HTML should take less than 200ms to be fully downloaded. Optimize your code and place your web servers closer to your users to ensure lower Time-To-First-Byte (TTFB) and complete document load.
  • Document response size: To ensure quick document load, limit your initial HTML document size to less than 200KB.
  • Head size: Calculates the bit size of the 'head' element. It’s useful to compare it with the size of the 'body' element.
  • Body size: Calculates the bit size of the 'body' element. It’s useful to compare it with the size of the 'head' element.
  • Number of DOM elements: Each DOM element requires client-side compute resources (and time) to be rendered as a graphical element in the user interface. Thus, limit their number to 1500 DOM elements per page for faster load speeds.

> Meta Tags

Meta Tags embedded in a web page really helps users and search engines quickly understand its purpose. These will directly affect its click-through rate when appearing in search results or social media networks. Take the time to finely tune them and capture a bigger and more qualified audience.

Those are the meta tags we analyze for you:

  • Title length: Optimized title should contain between 50 to 60 characters to correctly display in search results.
  • Description length: Formulate an informative and relevant meta description for each page without stuffing it with keywords. Best is to keep bit size characters.
  • Keywords: Even if those are now mostly ignored by search engines, carefully check that provided meta keywords are relevant to the page.
  • AMP version: Providing an AMP version of a page will boost its rankings for mobile users as it drastically speeds up page loading times.
  • Open Graph title: Define a relevant title to be displayed when embedding the page in social networks. This deeply influences click-through rates of such links shared in external platforms.
  • Open Graph image: Define the image to be displayed when embedding the page in social networks. This greatly influences click-through rates of such rick links shared in external platforms.
  • Schema types: Add at least one Schema type for each of your pages as this helps search engines understand the nature of its content and more adequately rank it for relevant search queries.

> Content

Instantly assess the text structure and images of the specified web page. Retrieve:

  • H1 heading: This is the most important heading element of an HTML document and should make clear to visitors that they will get what they are looking for when consuming that page.
  • H1/H2/H3/H4 heading counts: We recommend to use at least one iteration of each heading level to structure a page’s text content and make it easy to skim through.
  • Text/HTML ratio: To improve a page’s value and online visibility, make sure its text content makes for 25% to 70% of its total document size.
  • Total number of images: Relevant images keep users reading. Do your best to insert at least 5 in-context images within your text to make it more appealing and engaging.
  • Images without alt text: All images should contain a descriptive alternative text. This helps those images rank better in search engines (eg. Google Images) and bring additional organic traffic to your site.
  • 3rd party images: Host images on your own domain and via CDN when possible. This will increase domain authority and SEO while relying less on 3rd-party services to fully load your page.

> Links

We thoroughly scan the page to get to know:

  • All links count: It’s recommended to embed 20 to 50 highly useful links within each page. Those can help internal navigation or even link to external resources. This helps search engines determine the authority of its content and crawl your site efficiently. Be certain there are no broken links in your pages.
  • Internal links: Link to other relevant pages of your site to provide your visitors with a seamless navigation. For example, they can be used in dedicated menus or within the main text content.
  • External links: Linking to external pages when highly relevant provides additional value to your visitors. Be sure to use rel='noopener' and target='_blank' attributes when embedding external links to open them in a new browser tab instead of reusing the same tab. This ensures your page stays open in the browser and reduces bounce rate.
  • If each link has valid and descriptive anchor text: Do not use generic wordings (eg. “Click here”, “Link”) as anchor text. Instead, use specific keywords you’d like that page to rank for (eg. “SEO Audit”).

> Performance

Page load performance strongly impacts the user experience and search engines know that. That’s why it greatly affects a web page’ search result rankings. You should continuously monitor and improve it in order to exceed users’ expectations and steadily beat your competition in search results.

In a few seconds, we calculate the following performance metrics on any page:

  • Speed index: This determines how quickly the visible contents of a page gets populated.

> Accessibility

Each visitor is unique. That’s why you need to design your pages in a way they are correctly readable and accessible for most of them. Search engines prioritize web pages that are well written and which help consume its content.

Those are the properties factored in to compute the accessibility of a page:

  • No duplicate ID attribute: Each ID in your HTML document must be unique to prevent assistive technologies from partially reading a page’s content.
  • HTML has lang attribute: Define the lang attribute of the element in order that screen readers pronounce the text of the page in the correct language.
  • HTML lang is valid: lang attribute of the element should be defined with a valid BCP 47 language.
  • Valid lang attributes: lang attribute of any text-containing DOM element should be defined with a valid BCP 47 language.
  • Images have alt attribute: It’s best practice to add an alternative text (‘alt’ attribute) to every 'img' element on a page. For informative images, its value should be a short description. For decoration images, you can leave it empty.
  • Form elements have labels: Ensure each form element (eg. 'input') provides a relevant text label to make them readable to assistive technologies. Even mouse and touchscreen users benefit from such labels as it enlarges the click target.
  • All links have names: Make sure each link contains relevant anchor text. This is a powerful way to make other internal pages rank higher for specific keywords.
  • Enough color contrast: It’s important to keep text highly contrasted with its background. Failing to do so will negatively impact the experience of most users as they will have a hard time to decrypt your content.
  • Lists are well-formed: Make sure to only use list items 'li' or script supporting elements within lists 'ul' or 'ol'.
  • List items within proper parents: List items 'li' needs to be contained within parent 'ul' or 'ol' elements in order to be correctly interpreted by screen readers and other assistive technologies.
  • No page auto refresh: You shouldn’t be using the 'meta http-equiv='refresh'' tag as it forces the page to automatically reload after a finite amount of time. This often confuses users, affects their experience and makes them leave the page prematurely.
  • Meta viewport allows zoom: Do not use the user-scalable='no' and maximum-scale parameters for the 'meta name='viewport'' element as it disables browser zoom on a web page. This jeopardizes the experience of any user who relies on that zoom feature to comfortably read its text content.
  • Correct font size: Most search engines understand how easy it is to read a page on smaller-screen devices and penalize ranking of pages which are not. Do not use font size smaller than 12px as they are not legible on mobile devices without zooming in and out.

> Best practices

There is a myriad of other SEO best practices advocated by major protagonists in Web technologies. We check them all against a page to help you further optimize it for free organic traffic:

  • Avoid application cache: AppCache manifest declaration is deprecated and shouldn’t be used anymore.
  • Uses HTTPS: All sites should encrypt their traffic via SSL, including when not handling sensitive information. That’s the de facto industry standard and you need to make sure your SSL certificate is valid and covers all your (sub-)domains.
  • Uses HTTP2: You should use version 2 (or more recent) of HTTP protocol for loading the page document and all its resources. This guarantees faster load times and less data moving over the connection. This can particularly boost your mobile SEO.
  • No document.write(): Avoid using such JavaScript method as this can drastically slow down your page by tens of seconds. Even Google Chrome blocks the execution of document.write(). So, simply do not use it.
  • External links use rel='noopener': When linking to an external site with the target='_blank' attribute, you can expose your site to security and performance issues.
  • No geolocation on page start: Avoid requesting your users for the geolocation browser permission at page load. As this breaks their trust, most users instinctively leave the website or reject such permission requests, when they are not activated at the right moment.
  • No notification on page start: Avoid requesting your users for the notification browser permission at page load. This breaks the user experience. Instead, ask such permission after any relevant and explicit user action (eg. click on a button).
  • Doctype defined: Inserting the declaration at the very beginning of each of your pages is necessary. It prevents browsers from switching to a non-standard mode, which can break your entire page.
  • No vulnerable libraries: Once a vulnerable library is detected on a web page, an intruder can easily perform an attack and put your website and users at risk. Regularly run this audit and remove vulnerable libraries to make sure you keep your pages safe.
  • Avoid deprecated APIs: As deprecated APIs are regularly removed from recent browser versions, web page functionality might break if it keeps using them.
  • Allow paste to password field: For security reasons, it’s best practice to let users directly paste characters in password fields instead of forcing them to type a password down. Keyloggers have harder times capturing passwords injected from the clipboard compared to passwords typed via keyboard.
  • No errors in console: We double check that no JavaScript error occurs when loading the page. This would be a credible hint that something’s wrong in the page and user experience might be affected.
  • Images have correct aspect ratio: We flag when a rendered image has an aspect ratio that’s arguably different from its natural aspect ratio (the aspect ratio in its source file). When different, this often distorts them and breaks the user experience.


That’s also the opportunity to check how much a page respects the Progressive Web Application (PWA) framework. This is a relatively recent way of building, serving and running a web application inside a browser. It provides faster loading times, new features and a generally better experience to the users.

Let’s recap the elements you need to set up and be PWA-ready:

  • Load fast enough: Determines if a web page loads quickly enough on mobile devices to guarantee a great experience for your mobile visitors.
  • Redirects HTTP to HTTPS: As all sites should be protected with SSL encryption, we recommend that you automatically redirect HTTP requests to HTTPS requests.
  • Has meta viewport: The page document needs a viewport meta tag to render it correctly on all devices. If it’s invalid or absent, mobile devices render pages at typical desktop screen widths and then scale the pages down, making them difficult to read.
  • Content sized correctly: The viewport is the part of the browser window in which your page's content is visible. We flag pages whose width isn't equal to the width of the viewport.
  • Works without JavaScript: We check if the page provides a fallback mechanism when JavaScript is disabled in the browser.
  • Themed address bar: For improved user experience, it’s recommended to set up a ‘theme-color’ meta tag in the page's HTML in order to colorize the mobile browser address bar. This unifies the user interface in a unified and integrated color theme.


  1. Run this SEO site audit every time you perform a change in your web page or infrastructure. This helps you rollback or fix any new issue quickly before hitting your visitors.
  2. Combine the SEO audit with a detailed page speed audit. Doing so, you’ll continuously find ways to improve the performance of any page, provide a better user experience and ultimately gain bigger free traffic.
  3. Use the SSL Checker to verify the certificate of any domain.
  4. Start a free trial at Semrush and automate the continuous SEO analysis (and much more!) of your entire website. That’s the most effective and easiest way to build huge free organic traffic to your Web application in record time.