Easily build validated json-ld structured data markup for any webpage. Based on schema.org specification
Nice
Does not have enough types available, need services and other useful types.
Used it quite extensively. now it doesn't do more than tell me there is a schema on the page but when i click tester, it says there is no schema on the page. so the two tabs do not talk to each other or something. I know it is free, but I get more from the google testing. Going to miss seeing it in my extensions bar.
https://www.mertazizoglu.com/
Ryte
https://defaced.dev
OpenLink Software
Amin Foroutan
nodeandlink
http://www.seo-extension.com/
https://ahrefs.com
https://marketingsyrup.com
https://viewrenderedsource.com
Break The Web
https://seominion.com/