methods 5 cards
Which request methods are SAFE?
GET, HEAD, OPTIONS, TRACE — their defined semantics are read-only.
safe method
Which methods are idempotent but NOT safe?
PUT and DELETE.
idempotent method
Is POST idempotent? Is PATCH?
Neither. That's why a client/proxy must not automatically retry them after a network failure.
idempotent method
Does "safe" mean the server does nothing?
No — a GET may still log the hit or increment a counter. Safe is a promise about client intent and responsibility, not server inaction.
safe method
A DELETE succeeds, then the client retries it and gets 404. Was DELETE idempotent here?
Yes. Idempotency is about the *intended effect on the server* (resource stays deleted), not about identical response codes.
idempotent method
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