Communication Protocols Every Developer Should Know

Protocols are the rules that govern how apps talk to each other. They define message formats, how connections start and stay open, and how errors are reported. For developers, a solid grasp of a few core protocols helps you design reliable APIs, diagnose issues faster, and build scalable services.

HTTP and HTTP/2 Most web apps rely on HTTP. HTTP/1.1 uses a text-based request/response model with headers. HTTP/2 adds multiplexing, header compression, and server push, which reduce latency in many apps. When you call a public API or load a web page, HTTP is usually the carrier. TLS (HTTPS) protects the data in transit.

Real-time and streaming For live chat or dashboards, WebSocket keeps a single long-lived connection. Server-Sent Events offer a lighter one-way stream. Both rely on HTTP or a compatible upgrade, depending on your stack, and they enable timely updates without polling.

Messaging for services Microservices and IoT often use dedicated messaging protocols. MQTT shines on low-bandwidth devices with small messages. AMQP, used by many message brokers, supports reliable delivery, queues, and flexible routing. For internal service calls, gRPC provides fast, typed RPC over HTTP/2 with strong contract guarantees.

Data formats and serialization JSON is common for its readability. Protobuf or MessagePack offer compact, faster payloads, useful in mobile or high-traffic apps. Pick a format that matches your performance goals and tooling. API contracts, versioning, and clear field definitions help avoid breaking changes.

Security and practice TLS encrypts data in transit. OAuth 2.0 and OpenID Connect handle user authentication for APIs. Regularly rotate keys, validate certificates, and keep dependencies up to date. Simple checks, like verifying hostnames and token scopes, improve security without slowing you down.

Choosing the right protocol No single protocol fits all. REST over HTTP is great for public APIs and simple clients. gRPC shines inside a service mesh or microservice suite with strong typing. MQTT helps devices in tight networks. Frame choices around data needs, latency, and reliability, then test with real traffic to confirm performance.

Key Takeaways

  • Start with HTTP for public APIs, then add HTTP/2 features to reduce latency.
  • Use WebSocket or Server-Sent Events for real-time updates; choose MQTT or AMQP for messaging at scale.
  • Pick data formats (JSON, Protobuf, MessagePack) based on readability, size, and speed.