Here’s a comparison between HTTP/1, HTTP/2, and HTTP/3 in a table format:
| Feature | HTTP/1 | HTTP/2 | HTTP/3 |
|---|---|---|---|
| Multiplexing | No (Serial processing) | Yes (Concurrent processing) | Yes (Concurrent processing) |
| Header Compression | No (Headers are sent in plaintext) | Yes (HPACK compression) | Yes (HPACK compression) |
| Connection Reuse | No (Each request requires a new TCP connection) | Yes (A single connection can be reused for multiple requests) | Yes (Single connection can be reused for multiple requests) |
| Request Prioritization | No (All requests are treated equally) | Yes (Requests can be prioritized) | Yes (Requests can be prioritized) |
| Server Push | No | Yes (Server can push resources to the client) | Yes (Server can push resources to the client) |
| TLS Required | No (Optional) | Recommended, but optional | Yes (Mandatory for HTTP/3) |
| Transport Protocol | TCP | TCP | UDP |
| Binary Framing | No (Text-based protocol) | Yes (Binary framing) | Yes (Binary framing) |
Multiplexing:
- HTTP/1: Processes requests and responses in a serial manner, leading to head-of-line blocking.
- HTTP/2 and HTTP/3: Introduce multiplexing, allowing multiple streams (requests and responses) to be sent concurrently over a single connection.
Header Compression:
- HTTP/1: Headers are sent in plaintext for each request and response.
- HTTP/2 and HTTP/3: Use HPACK compression to reduce the size of headers, improving efficiency.
Connection Reuse:
- HTTP/1: Requires opening a new TCP connection for each request, leading to latency.
- HTTP/2 and HTTP/3: Allow multiple requests and responses to be sent over a single, reused connection.
Request Prioritization:
- HTTP/1: Treats all requests equally without prioritization.
- HTTP/2 and HTTP/3: Allow prioritization of requests, improving the loading of critical resources.
Server Push:
- HTTP/1: Doesn’t support server push.
- HTTP/2 and HTTP/3: Allow the server to push resources to the client before they are requested.
TLS Requirement:
- HTTP/1: Optional.
- HTTP/2: Recommended but optional.
- HTTP/3: Mandatory.
Transport Protocol:
- HTTP/1 and HTTP/2: Use TCP.
- HTTP/3: Uses UDP for improved performance.
Binary Framing:
- HTTP/1: Text-based protocol.
- HTTP/2 and HTTP/3: Use binary framing, improving efficiency and reducing parsing complexity.
It’s important to note that while HTTP/2 and HTTP/3 bring significant performance improvements, the adoption of each version depends on various factors, including server and client support. HTTP/3 is the latest version, and its adoption is growing, especially for websites aiming to leverage the benefits of QUIC.