How Do Programs Talk to Each Other? JSON, XML, Protobuf, RPC, REST, gRPC, GraphQL and Messaging

Tue, 20 Oct 2026 20:00:00 +0000

A mobile app asks a server for a user’s orders. The server asks a payment service whether an order was paid, tells a warehouse system to ship it, and announces to anyone interested that it has shipped. A code editor asks a language server where a function is defined; an AI agent asks a tool to read a file. All of these are programs talking to other programs, and every one of those conversations rests on two decisions: how the data is encoded into bytes, and how the conversation is shaped, as a function call, a request for a resource, a query, a stream or a message dropped in a queue.

RPC on Artur Rios Lab

How Do Programs Talk to Each Other? JSON, XML, Protobuf, RPC, REST, gRPC, GraphQL and Messaging