find issue in the website - SERP Analysis

https://try.powermapper.com/Demo/SortSite

https://www.isitdownrightnow.com/

https://www.reddit.com/r/shopify/comments/1ginkos/best_tools_to_check_my_website_for_problems/

https://www.deadlinkchecker.com/

https://www.powermapper.com/products/sortsite/checks/website-error-checker/

https://www.quora.com/If-a-website-I-use-gives-an-error-how-can-I-check-to-see-if-its-a-problem-on-my-side-or-theirs

https://issuetracker.google.com/

https://hostingdiscussion.com/threads/website-error-checker-tools-in-free-way.82013/

https://www.sitepoint.com/community/t/html-error-finder/15223

https://developer.chrome.com/docs/devtools/issues