Communication Protocols You Should Know: HTTP/2, gRPC, QUIC

Three main protocols shape how data travels on the web today: HTTP/2, gRPC, and QUIC. They are designed to speed up connections, reduce delays, and make communication more reliable. Understanding them helps you pick the right tool for the job and avoid common bottlenecks.

HTTP/2 fixes many issues of HTTP/1.1. It allows multiplexing, so many requests share a single TCP connection without waiting for earlier responses. It also uses header compression to save bandwidth. Because HTTP/2 runs over TCP, it gains reliability, but head‑of‑line blocking can still slow some flows if a single stream stalls.

gRPC is a framework for remote procedure calls. It sits on HTTP/2 and adds a clear contract with Protobuf messages. This makes messages small and fast to parse. gRPC supports streaming and bidirectional communication, which helps services share state in real time. It is a strong choice for internal microservices, but browser clients often need gRPC‑Web or a REST fallback.

QUIC is a newer transport layer built on UDP. It brings fast connection setup, built‑in encryption with TLS 1.3, and multiple independent streams inside one connection. The result is often lower latency and better resilience on lossy networks. HTTP/3 uses QUIC, so adopting QUIC often goes hand in hand with moving to HTTP/3.

In practice, you might choose based on your goals. HTTP/2 (and HTTP/3) works well for public APIs and web pages. gRPC shines for internal APIs with rigid schemas and strong tooling. QUIC helps where mobile users or unstable networks demand snappy connections, particularly in modern web apps that adopt HTTP/3.

Tips for deciding:

  • Check client and firewall support, especially for UDP when enabling QUIC.
  • Consider developer experience: gRPC gives strong contracts; HTTP APIs are broadly supported in browsers.
  • Plan migrations carefully, since transitions affect servers, proxies, and caches.
  • Run real‑world tests to measure latency, throughput, and connection times.

Key Takeaways

  • HTTP/2 improves web performance through multiplexing and efficient headers, but runs over TCP.
  • gRPC offers fast, typed communication with streaming, best for internal services.
  • QUIC lowers connection setup time and reduces blocking, and underpins HTTP/3 for faster web apps.