When to use REST vs GraphQL vs gRPC

Here you go:
Most arguments about this don’t get to the heart of the matter.

It’s not about which one is “better.” It’s about which one works for you.
I have worked on systems that used all three, and the teams that had trouble weren’t using the wrong technology  they were using the right technology in the wrong place.

Let me explain it to you.

Use REST when:

→ You’re making a public API
→ Your team is small and you want things to be simple
→ You need the most compatibility (with browsers, mobile, and third-party tools)
→ Your data model is stable and predictable

REST is not interesting. That’s a feature, not a problem. It’s been around for a long time, every developer knows how to use it, and every tool works with it. When you open up an API to the outside world, you want it to be boring and predictable. Don’t build things that don’t need to be built.

Use GraphQL when:

→ You have multiple clients with different data needs (mobile vs web)
→ You’re tired of getting too much or too little data
→ Your frontend team works faster than your backend team
→ You’re building a product with a complicated data model that connects to other data models

GraphQL gives the client power. The frontend doesn’t send any extra data — it only asks for what it needs. The backend doesn’t decide what data to send. This sounds great until you make it public and someone sends a query that joins 12 tables and crashes your database. GraphQL is great for products, but it needs some rules. Rate limiting, query depth limits, and complexity analysis are all required.

Use gRPC when:

→ You need to communicate between services (microservices)
→ Performance is very important — milliseconds matter
→ You need strong typed contracts between teams
→ You’re okay with more complexity in exchange for speed

gRPC runs on HTTP/2, uses Protocol Buffers instead of JSON, and is much faster than both REST and GraphQL for internal communication. What do you have to give up? It’s not easy to use in a browser and takes longer to learn. But when you have ten microservices talking to each other thousands of times a second, that performance gap is real and it matters. The strict schema also makes teams write contracts ahead of time, which cuts down on a whole class of integration bugs.

The real answer?

Most serious production systems don’t choose just one.

→ REST for public APIs — stable, compatible, and easy to document.
→ GraphQL for frontend and backend — flexible and easy to change.
→ gRPC for internal microservices — fast, strongly typed, built for scale.

What do I see most often? Teams get attached to one technology and try to make it do everything.

They make a gRPC API for their mobile app. Or they expose raw GraphQL publicly with no protection. Or they build a microservices mesh with plain REST and wonder why it’s slow.
Know your level. Use the right tool for the job.