System Design (3): API Design — REST, gRPC, GraphQL, and Choosing Wisely

Tue, 15 Jul 2025 09:00:00 +0000

In 2015, Facebook published a blog post introducing GraphQL, describing how their mobile app was drowning in REST API calls. A single news feed screen required data from posts, users, comments, likes, and media — each a separate endpoint, each returning far more data than the client needed. The over-fetching was killing mobile performance on slow networks. GraphQL was their solution, but it was not a universal solution.

Every API style exists because it solves a specific set of problems well, and every API style creates new problems. The skill is matching the right protocol to the right context.

REST on Chen Kai Blog

System Design (3): API Design — REST, gRPC, GraphQL, and Choosing Wisely