3 free resources on this topic. Everything here is free and hand-picked. You can also search within this topic.
A free reference and debugger for JSON Web Tokens, the compact signed tokens used to pass login and permission claims between systems, with libraries listed by language.
A technical article covering API authentication and authorization mechanisms such as API keys, OAuth, and JWTs, comparing their trade-offs and describing common failure modes engineers encounter when implementing them.
Free step-by-step tutorials on adding login, single sign-on, and OAuth to your own app — one of the clearest sources on authentication that is not a sales page.
Why I recommend it: Free reading. FusionAuth sells a hosted auth product, so expect the examples to use it; the concepts and code patterns transfer to other auth libraries.
