HTTP OPTIONS Method Explained: The Key to Understanding CORS Preflight

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The HTTP OPTIONS method is a standard request type that allows clients to query a server about the communication capabilities it supports for a specific resource. Unlike GET or POST, OPTIONS does not retrieve or modify data — it simply returns informational headers such as the Allow header, which lists supported HTTP methods. Developers rarely send OPTIONS requests manually; instead, browsers automatically trigger them before certain cross-origin requests in a process called a Preflight Request. Understanding OPTIONS is considered essential groundwork before learning how CORS Preflight Requests function.

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