Terminology » Networking Basics » HTTP 1 vs HTTP 1.1 vs HTTP 2: Key Differences Explained

HTTP 1 vs HTTP 1.1 vs HTTP 2: Key Differences Explained

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This page compares HTTP 1, HTTP/1.1, and HTTP/2, highlighting the key differences between them.

Introduction:

HTTP, or Hypertext Transfer Protocol, is the foundation of the World Wide Web. Browsers use it to load web pages.

HTTP connection

Example: When you enter a URL like “http://www.google.com” into your browser, the browser sends an HTTP request to the web server. The web server then sends an HTTP response back to the client (your browser) with the content of the.jpgage.

HTTP 1 Protocol

  • HTTP methods include GET, PUT, and POST.
  • Specifies the request target, such as a URL or port.
  • Uses text-based commands for HTTP requests.
  • Achieved official recognition in 1996.
  • Introduced new response headers that allowed for multiple file types (e.g., plain text, HTML, images).

HTTP 1.1 Protocol

  • Released in 1997.
  • Like HTTP 1, it uses text-based commands for HTTP requests.
  • Added several performance enhancements, including:
    • Caching
    • Request pipelining
    • Keep-alive connections
    • Transfer encoding
    • Byte range requests
  • Can load one request at a time, meaning only one request per TCP connection is possible.

HTTP 2 Protocol

  • Released in February 2015 by the IETF.
  • Binary protocol (not textual like HTTP 1 and 1.1).
  • Fully multiplexed.
  • Interleaves multiple requests and responses in parallel without blocking any of them.
  • Uses a single TCP connection to deliver multiple requests/responses in parallel.
  • Uses header compression to reduce overhead.
  • Allows servers to proactively “push” responses into client caches.
  • Removes unnecessary HTTP/1.x workarounds (e.g., image sprites, domain sharing).
  • Less error-prone than HTTP/1.x.

Note: HTTP/3 was released in late 2019 and is based on the QUIC protocol.