REST
The dominant style for web APIs. Resources addressed by URLs, manipulated via HTTP methods. Universal, simple, and cacheable.
GraphQL & tRPC
Two alternatives to REST. GraphQL lets clients specify exactly what they want; tRPC eliminates the API layer entirely for TypeScript-to-TypeScript apps.
Real-Time APIs
When the server needs to push data to the client — chat, live dashboards, LLM streaming — request/response isn't enough. WebSockets, SSE, and gRPC fill the gap.
WebRTC
How browsers open low-latency audio, video, and data channels directly between peers (or to a server that speaks WebRTC) — SDP, ICE, STUN, TURN, and the full handshake from offer to "connected".
Queues & events
How async work, fan-out, and decoupling actually work in production — RabbitMQ, Kafka, SQS, Redis Streams, the at-least-once promise, dead-letter queues, event sourcing, and when this complexity is worth it.