The title tag is the HTML element that specifies the title of the webpage. The title tag is displayed at the top of your browser, in the search results, as well as in the bookmarks bar.

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The meta description is an HTML tag that provides a short and accurate summary of the webpage. The meta description is used by search engines to identify a webpage's topic and provide relevant search results.

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The h tags represents the headings of the webpage. The h1 tag is the most important h tag, and describes the main topic of the page, while the rest of the tags describe the sub-topics of the webpage.

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The webpage's content should contain relevant keywords that can also be found in the title of the webpage.

The alt attribute specifies an alternate text for an image, if the image cannot be displayed. The alt attribute is also useful for search engines to identify the subject of the image, and helps screen readers describe the image.

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The SEO friendly URLs are URLs that contain relevant keywords with the webpage's topic, and contain no special characters besides slashes and dashes.

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The 404 webpage status inform the users and the search engines that a page is missing.

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A robots.txt file inform the search engines which links from the website can be accessed.

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The noindex tag instruct the search engines to not index the webpage.

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The in-page links should be kept at a minimum, to avoid issues with search engines not being able to crawl additional links from the webpage.

The lang attribute declares the webpage's language, helping search engines identify the language in which the content is written, and browsers to offer translation suggestions.

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The favicon is the icon that is being displayed in the browser's tab, when the webpage is being bookmarked, and sometimes even in search engine results.

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The text compression helps speeding up the webpage's load by compressing the HTML's content.

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The load time indicates the HTML's total load time, and does not include the external resources, such as images, scripts, or other resources.

The page size indicates the HTML's total size, and does not include the external resources, such as images, scripts, or other resources.

The HTTP requests represents the number of external resources present on the webpage.

The images format represents the images that are not served in a next-generation file format. Images served in a next-generation format improve the webpage's load performance.

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The defer attribute allows the browser to download the scripts in parallel and execute them after the webpage has been parsed, improving the webpage's load performance.

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The DOM size indicates the number of nodes the HTML webpage has.

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The HTTPS encryption helps protecting the user's security and privacy.

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The Google Safe Browsing indicates the webpage status for malware and phishing content.

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Email addresses posted in public are likely to be fetched by crawlers and then collected in lists used for spam.

The structured data tags help the search engines better understand the content of the webpage, and allows them to create rich snippets in search results.

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The meta viewport tag instruct the browsers how to render the viewport of the webpage.

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The meta charset tag specifies the character encoding, helping the browsers to better render the characters and symbols on the webpage.

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Sitemaps inform search engines about pages available for crawling on the website.

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Social media presence is becoming increasingly important as a ranking factor for search engines to validate a website's trustworthiness and authority.

The content length represents the number of words found on the webpage. The webpage should contain a decent amount of words.

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The text to HTML ratio represents the percentage of actual text compared to the percentage of HTML code on the webpage.

The style attribute contains CSS style rules that are applied to the element. Inline CSS code unnecessarily increases the webpage's size, and can be moved in an external CSS file.

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The deprecated tags represents the tags that are not supported HTML5 standard anymore, and could cause the webpage to be rendered incorrectly.

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