REST vs. GraphQL vs. gRPC: The Battle for Your Backend Architecture

For a long time, the answer to “How should our services talk to each other?” was simply: REST. It was the default. But in 2025, with the explosion of complex microservices and bandwidth-constrained mobile clients, “defaulting” to REST can be a costly architectural mistake.

We now have three heavy hitters in the ring: the reliable veteran (REST), the flexible graph (GraphQL), and the speed demon (gRPC).

I want to break down how to choose between them, because the “best” choice is almost entirely dependent on your specific constraints regarding caching, payload size, and developer experience.

1. REST: The Standard for Public APIs

REST remains the king of caching. Because it leverages standard HTTP caching mechanisms (ETags, Cache-Control headers), it is incredibly robust for content that doesn’t change every millisecond.

• Best for: Public-facing APIs, simple CRUD applications, and systems where intermediary proxies need to cache responses to save load.
• The Downside: The dreaded “Over-fetching” (getting too much data) and “Under-fetching” (needing to make 5 calls just to assemble one screen).

1. GraphQL: The Frontend Developer’s Dream

GraphQL solved the rigidity of REST. It gives the client the power to ask for exactly what it needs and nothing more.

• Best for: Mobile applications (where bandwidth is expensive), complex dashboards with nested data, and teams where frontend and backend need to iterate independently.
• The Downside: Caching is hard. Because almost every request is a POST to a single endpoint, you lose the free HTTP caching capabilities of REST. You often have to build complex application-level caching logic.

1. gRPC: High-Performance Internal Comm

gRPC uses Protocol Buffers (Protobuf) a binary format that is much smaller and faster to serialize than JSON. It runs over HTTP/2, supporting bidirectional streaming.

• Best for: Low-latency internal microservices (Service-to-Service), real-time streaming, and polyglot environments (where Service A is Python and Service B is Go).
• The Downside: It’s binary, meaning you can’t just curl it and read the output easily without tools. Browser support also generally requires a proxy (like Envoy) to translate HTTP/1.1 to gRPC web.

The “Hidden” Variable: Versioning

This is where the headaches start.

• REST: Usually requires “global” versioning (e.g., /v1/users, /v2/users). It’s clean but can lead to code bloat.
• GraphQL: Encourages “Evolution” rather than versioning. You depreciate old fields and add new ones, but you technically never break the schema.

gRPC: Protobuf has built-in backward compatibility rules (numbering fields). If you stick to the rules, old clients can still read new messages.