HTTP/1.1, HTTP/2 and HTTP/3

Shared semantics, different transport designs.

UnderstandStudy an examplePractise

Understand the concept

HTTP/1.1 supports persistent connections; pipelining saw limited deployment because of practical problems. HTTP/2 multiplexes streams over a connection and uses HPACK. TCP packet loss can still stall progress across that connection.

HTTP/3 uses QUIC with independently progressing streams and TLS 1.3 integration. UDP does not make it unreliable or unencrypted; QUIC provides those properties. Streams still share network capacity and congestion constraints.

HTTP/3 is not guaranteed faster for every network. Early 0-RTT data can be replayed and requires careful treatment for unsafe operations. Inspect the actual negotiated protocol rather than inferring it from a website label.

WHEN TO USE IT

Understand real transport bottlenecks.

COMMON PITFALL

Claiming HTTP/3 solves all latency and security problems.

01 / PRACTICE

One topic. Three levels of depth.

HTTP / illustrative example

HTTP/1.1: text framing / usually TCP

Readable message framing.

This page does not send requests to external servers. Messages are readable HTTP/1.1 illustrations, not HTTP/2 or HTTP/3 wire dumps. example.test is reserved for examples. Run commands and JavaScript only in your own test environment; never publish real tokens or cookies.

02 / YOUR TURN

Try it yourself first.

Does HTTP/2 eliminate TCP-level head-of-line blocking?

Show the solution and explanation

Worked solution

HTTP/2 multiplexing ≠ independent TCP delivery

No. HTTP/3 uses a different transport model at that layer.

RasimAtaberkŞahin

Understand the concept

One topic. Three levels of depth.

Try it yourself first.