Communication protocols are the agreed rules that let systems exchange data reliably over a network — governing message format, sequencing, error handling, and delivery — from foundational layers like TCP and HTTP up to API-facing protocols such as gRPC and WebSocket.
Communication Protocols
Communication protocols are the agreed rules that let two systems exchange data over a network without ambiguity. They define the shape of messages, the order they arrive in, how errors are detected and recovered, and how a connection is opened and closed. Everything in the API economy rides on a stack of them — from IP and TCP at the bottom, through HTTP, up to the protocols APIs speak directly.
- Message format and framing - The agreed structure that lets a receiver know where one message ends and the next begins.
- Sequencing and delivery - Ordering, acknowledgment, and retransmission rules that make an exchange reliable across an unreliable network.
- Error handling - Defined status signals and recovery behavior so both sides agree on what went wrong.
- Layering - Higher-level protocols like HTTP, gRPC, and WebSocket build on lower ones rather than reinventing the transport.
Which protocol an API speaks shapes almost everything downstream about its developer and machine experience — HTTP/JSON for broad reach, gRPC over HTTP/2 for low-latency service-to-service calls, WebSocket for streaming. When I score providers, protocol choice is one of the first things that signals who an API is really built for, and it increasingly matters for agents, which need to know exactly how to connect before they can consume anything.
Referenced on the API Evangelist blog
Where this standard shows up across sixteen years of my writing at apievangelist.com — how it fits into API design, governance, and the agentic turn.
