REST vs gRPC
REST vs gRPC explained. Why gRPC is faster for internal services and why REST is still better for public APIs.
REST sends human readable JSON over standard HTTP and is easy for anyone to consume. gRPC sends compact binary Protobuf messages over HTTP/2, which is faster and more efficient, but harder to read directly and less friendly for public facing APIs.
REST vs gRPC at a glance
| REST | gRPC | |
|---|---|---|
| Data format | JSON, text based | Protobuf, binary |
| Protocol | HTTP/1.1 typically | HTTP/2, supports multiplexing |
| Human readability | Easy to read and debug directly | Requires tools to decode binary messages |
| Performance | Good, but heavier than binary formats | Faster, smaller payloads, lower latency |
| Streaming support | Limited, typically request and response only | Native support for streaming in both directions |
| Best for | Public APIs, browser clients | Internal microservice to microservice calls |
When to use each
Choose REST when
- You are building a public API that third parties or browsers will consume directly.
- You want requests to be easily readable and debuggable without special tooling.
- Your clients need broad compatibility without generating code from a schema.
Choose gRPC when
- You are building internal microservice to microservice communication.
- Performance and low latency matter more than human readability.
- You need real time streaming data flowing in both directions.
Why gRPC is faster
REST typically sends JSON, a text format that is easy to read but takes more bytes to represent the same data, over HTTP/1.1, which opens a new connection or waits in line for each request. gRPC sends Protobuf, a compact binary format that is much smaller on the wire, over HTTP/2, which can send multiple requests over a single connection at the same time. Both of those differences add up to meaningfully lower latency.
The trade off you give up
That speed comes at a cost. A gRPC message is binary, so you cannot just read it in a browser network tab the way you can with JSON. You also need to define your service with a Protobuf schema and generate client and server code from it, adding a build step that a simple REST API does not need. This is exactly why gRPC dominates internal service to service calls but rarely shows up as a public facing API.
A sharp point to raise is that many companies use both. gRPC handles fast internal communication between microservices, while a REST or GraphQL layer sits at the edge, translating for public clients like browsers and mobile apps that expect JSON.
Frequently asked questions
Can a browser call a gRPC service directly?
Not natively in most cases. Browsers do not support the raw gRPC protocol well, so a common pattern is grpc-web, which needs a small proxy to translate between the browser and the gRPC backend.
What is Protobuf?
Protocol Buffers, or Protobuf, is a binary serialization format from Google. You define your data structures in a schema file, then generate code that efficiently encodes and decodes that data, much smaller than the equivalent JSON.
Is gRPC always better than REST?
No, it depends on the use case. REST remains simpler, more widely supported, and easier to debug, which is why it is still the default choice for public APIs even though gRPC often wins for internal performance.
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