meta tags analyzer

https://www.seocentro.com/tools/search-engines/metatag-analyzer.html

AMP validation

https://search.google.com/test/amp

make your web site faster

https://gtmetrix.com/

seeing meta tags via web site

https://www.heymeta.com/

in site duplicate content

http://www.siteliner.com/

Steel Buildings & Metal Roofing - Total Value | Mueller, Inc

structured data testing tool

https://search.google.com/structured-data/testing-tool/u/0/https://search.google.com/structured-data/testing-tool/u/0/