REST vs gRPC vs GraphQL

Opening Scenario

Your team is building a new service. A frontend engineer asks for a /user endpoint that returns everything about a user — but the mobile app only needs the name and avatar, and it's complaining about slow loads. Meanwhile, a backend engineer wants service-to-service calls between 12 microservices to be fast and type-safe. Three engineers, three different pain points, all from the way your API is designed.

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Question Progression

1. What problem is REST actually solving?

Question: REST is everywhere — every tutorial starts with it. But before asking whether to use something else, what does REST actually give you, and what are its limits?

Reasoning: REST (Representational State Transfer) isn't a protocol — it's a set of architectural constraints layered on top of HTTP. It maps operations to HTTP verbs (GET, POST, PUT, DELETE) and organizes resources into URLs (/users/123, /orders/456). The benefit is that it uses standard…