What is HTTP/2: A Guide for the Curious

HTTP/2 is not just a trend; it's a substantial upgrade to the web's HTTP protocol. Originating from Google's SPDY protocol, it was standardized by the Internet Engineering Task Force (IETF) in 2015. For those who love performance and security, HTTP/2 is a big deal.

Why HTTP/2 Matters

The driving force behind HTTP/2 was to reduce latency and improve web page loading speed. This is especially vital for services like Uploadcare, where efficient file management and content delivery are paramount.

Key Features

  • Multiplexing: Allows multiple requests and responses to be sent simultaneously over a single TCP connection.
  • Server Push: Enables the server to send additional data in response to a single client request.
  • Header Compression: Reduces overhead by compressing HTTP headers.
  • Prioritization: Allows for more essential resources to load before others, enhancing user experience.

How It Differs From HTTP/1.1

Ironically, HTTP/2 has shown to be slower in uploading files compared to HTTP/1.1. Peter Forsberg highlighted this in a blog post, noting that HTTP/2 requests take longer to complete and reduce throughput. Amazon engineers have partially addressed this, but the issue remains. Therefore, Uploadcare supports the option to upload using HTTP/1.1.

The Security Aspect

While HTTP/2 itself doesn't mandate encryption, all major browsers like Chrome and Firefox only support HTTP/2 over TLS. So, encryption is basically a given.

HTTP/2 and Uploadcare

We use HTTP/2 when the client supports this protocol version. Utilizing HTTP/2 brings advantages for end-users: content loading on web pages becomes faster. HTTP/2 is our preferred protocol version as it is supported by all modern browsers, enhancing the UX for end-users.

Criticisms and Challenges

  1. Complexity: Some believe the standard was rushed and is overly complicated.
  2. TCP Head-of-Line Blocking: HTTP/2 transactions can still be blocked due to CP-level issues.
  3. TEncryption Debate: The requirement for encryption has both supporters and critics, citing performance and necessity concerns.

What’s Next: HTTP/3

HTTP/2's successor, HTTP/3, is under development and aims to build upon HTTP/2's foundations while addressing its shortcomings.


HTTP/2 is more than an upgrade; it's a leap towards a faster, more secure internet. As we navigate the evolving landscape of web protocols, HTTP/2 serves as a robust tool for improving web performance and security, something we at Uploadcare take seriously.

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