Authentication: Proving Who Is Calling Your API
The second post in the API Security series — a practical tour of API keys, session cookies, bearer tokens, OAuth 2.0, OIDC and JWTs, plus how to verify a token correctly and where authentication quietly breaks.
Proving who is calling: API keys vs sessions vs bearer tokens, OAuth 2.0 grant types and OIDC, and JWT validation done right — the alg:none / algorithm-confusion pitfalls, verifying signature/exp/aud/iss, and access vs refresh token rotation.