Node.jsInterview preparation
Foundation·Concept·2 min read

HTTP/1.1 vs HTTP/2 vs HTTP/3?

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Definition:

HTTP versions preserve the basic request/response model but change how messages travel over the network. HTTP/2 multiplexes streams over one TCP connection, while HTTP/3 uses QUIC to avoid some transport-level blocking between streams. These improvements affect connection efficiency, not the need for correct API semantics.

Key points:

  • HTTP/1.1 reuses connections, but concurrent requests often need multiple connections.

  • HTTP/2 sends multiple streams over one TCP connection.

  • HTTP/3 uses QUIC over UDP, reducing cross-stream blocking caused by lost packets.

  • TLS protects transport; it is a separate concept from choosing an HTTP method or status code.

Interview point:

  • HTTP/2 still shares TCP packet-loss ordering across streams; HTTP/3 reduces that cross-stream dependency.
Adapted from 02_NODE_EXPRESS_HTTP.md · “HTTP/1.1 vs HTTP/2 vs HTTP/3?”. Code examples are study fragments. Difficulty and core labels are editorial estimates; version-specific behavior should be checked against your project.