At which layer in the OSI stack does the Hypertext Transfer Protocol operate?

Layer 1 is the Physical layer, concerned with electrical signals and physical media, not application protocols.

Layer 2 is the Data Link layer, which handles MAC addressing and framing between directly connected nodes.

Layer 3 is the Network layer, responsible for logical IP addressing and packet routing between networks.

Layer 4 is the Transport layer, which provides end-to-end delivery via TCP or UDP - HTTP rides on top of TCP but is not itself a transport-layer protocol.

Layer 5 is the Session layer, which manages session establishment and synchronization between communicating hosts.

Layer 6 is the Presentation layer, responsible for data encoding, encryption, and format translation between systems.

HTTP operates at OSI Layer 7 (Application layer), which defines protocols for direct interaction with end-user applications - HTTP provides the request/response messaging rules used by web clients and servers, making it a classic application-layer protocol.