The best free and online tools for testing and optimizing an application or website

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In this article, I will give you some useful online tools to ensure your website is efficient, does not contain errors and is optimized for search engines (SEO). These three characteristics are very important because they form a virtuous circle by mutually reinforcing each other. None should be overlooked.

Performance

After analyzing your website, GTMetrix will give you valuable tips to improve its performance.

• Minimize the amount of resource to reduce the number of HTTP requests (using sprites, merging files)
• Reduce the size of your resources. There are very good online compressors for images (TinyPNG), CSS and Javascript files.
• Specify image dimensions, the browser does not need to do this calculation
• Use the browser cache

Search Engine Optimization – SEO

You can check your ranking with SEO SiteCheckup. This tool will give you valuable information to improve your site’s visibility on the Internet.

• Using the basic HTML tags and attributes (title, description, h1, h2, alt…)
• Creation of the sitemap file
• Detection of broken links
• Detection of the social activity linked to your website, your presence on social networks

Technical validators

You should also make sure your site is valid from a technical point of view. I recommend the official developer tools provided by the World Wide Web Consortium (W3C). Each tool is specific for a particular purpose. For example, you will find a tool to validate:

• HTML files
• CSS files
• Links
• RSS newsfeed

It is not necessary to validate every page one by one. The validation of the homepage is usually sufficient.

Email

Your application is sending emails? With Mail tester, you can test the relevance and format of your emails. This tool will let you know if the emails you are currently sending are considered as spam and also give you advice to avoid such a situation.

• The content should adapt to the size of the screen (responsive design)
• An alternative raw text format should be attached for email clients that cannot render HTML
• The authentication of your emails should be properly configured (SPF, DKIM)

To give you an idea of your site’s performance compare to others, most of the tools quoted in this article will give you a score, now you have to increase it!