---
title: "What is GRPC?"  
description: "What is GRPC?"  
author: "Anubhav Sharma"  
published: 2026-01-12  
updated: 2026-01-12  
canonical: https://www.mindstick.com/interview/34440/what-is-grpc  
category: "api(s)"  
tags: ["api(s)", "api documentation"]  
reading_time: 5 minutes  

---

# What is GRPC?

> **gRPC** (Google Remote Procedure Call) is a **high-performance, open-source RPC framework** developed by Google that allows applications to **communicate with each other efficiently**, especially in **microservices architectures**.

Instead of sending raw HTTP requests like REST, [gRPC](https://answers.mindstick.com/qa/116121/why-is-grpc-generally-faster-than-rest) lets you **call a function on another server as if it were a local method**.

## 1. What problem does gRPC solve?

In distributed systems:

- Services need to talk to each other fast
- Data should be small and efficient
- APIs should be strongly typed
- Multiple languages should work together

gRPC solves these by using:

- [**HTTP/2**](https://www.mindstick.com/blog/303188/mitigating-rapid-reset-ddos-attacks-through-http-2-vulnerability-exploitation)
- [**Protocol Buffers (Protobuf)**](https://answers.mindstick.com/qa/116124/what-is-the-role-of-protocol-buffers-in-grpc-and-how-is-it-different-from-json-in-rest)
- **Code generation**

## 2. How gRPC works (Simple Flow)

- You define your API in a `.proto` **file**
- gRPC generates **client & server code**
- Client calls a method like a local function
- **gRPC:**

   - Serializes data using Protobuf
   - Sends it over HTTP/2
   - Deserializes on the server

- Server returns the response

## 3. Key Technologies Used

### 1. Protocol Buffers (Protobuf)

- Binary serialization format
- Smaller & faster than JSON
- Strongly typed

Example:

```plaintext
message UserRequest {
  int32 id = 1;
}
```

### 2. HTTP/2

gRPC uses HTTP/2, which supports:

- Multiplexing (multiple calls over one connection)
- Header compression
- Bi-directional streaming
- Low latency

## 4. Types of gRPC Calls

gRPC supports **4 communication patterns**:

### Unary (Request → Response)

Like REST

```plaintext
Client → Server → Client
```

### Server Streaming

```plaintext
Client → Server → (multiple responses)
```

### Client Streaming

```plaintext
(multiple requests) → Server → Response
```

### Bi-directional Streaming

```plaintext
Client ↔ Server (both stream continuously)
```

## 5. gRPC vs REST (Quick Comparison)

| Feature | gRPC | REST |
| --- | --- | --- |
| Protocol | HTTP/2 | HTTP/1.1 |
| Data Format | Protobuf (binary) | JSON (text) |
| Speed | Very fast | Slower |
| Streaming | Native support | Limited |
| Code Generation | Yes | No (manual) |
| Browser Support | Limited | Excellent |
| Typing | Strongly typed | Weakly typed |

## 6. When should you use gRPC?

### Best for:

- Microservices communication
- High-performance systems
- Internal APIs
- Real-time streaming
- Polyglot systems (Java, C#, Go, Python, etc.)

### Avoid when:

- Public APIs for browsers
- Simple CRUD apps
- SEO-based web apps

## 7. Languages Supported

gRPC supports many languages:

- C#
- Java
- Go
- Python
- Node.js
- C++
- PHP
- Ruby

## 8. Real-world Use Cases

- Google internal services
- Netflix internal APIs
- Kubernetes
- Cloud-native systems
- Real-time chat & telemetry systems

## 9. Simple Definition (Interview-friendly)

> **gRPC is a high-performance RPC framework that uses HTTP/2 and Protocol Buffers to enable fast, strongly-typed communication between distributed services.**

## Answers

### Answer by Anubhav Sharma

> **gRPC** (Google Remote Procedure Call) is a **high-performance, open-source RPC framework** developed by Google that allows applications to **communicate with each other efficiently**, especially in **microservices architectures**.

Instead of sending raw HTTP requests like REST, [gRPC](https://answers.mindstick.com/qa/116121/why-is-grpc-generally-faster-than-rest) lets you **call a function on another server as if it were a local method**.

## 1. What problem does gRPC solve?

In distributed systems:

- Services need to talk to each other fast
- Data should be small and efficient
- APIs should be strongly typed
- Multiple languages should work together

gRPC solves these by using:

- [**HTTP/2**](https://www.mindstick.com/blog/303188/mitigating-rapid-reset-ddos-attacks-through-http-2-vulnerability-exploitation)
- [**Protocol Buffers (Protobuf)**](https://answers.mindstick.com/qa/116124/what-is-the-role-of-protocol-buffers-in-grpc-and-how-is-it-different-from-json-in-rest)
- **Code generation**

## 2. How gRPC works (Simple Flow)

- You define your API in a `.proto` **file**
- gRPC generates **client & server code**
- Client calls a method like a local function
- **gRPC:**

   - Serializes data using Protobuf
   - Sends it over HTTP/2
   - Deserializes on the server

- Server returns the response

## 3. Key Technologies Used

### 1. Protocol Buffers (Protobuf)

- Binary serialization format
- Smaller & faster than JSON
- Strongly typed

Example:

```plaintext
message UserRequest {
  int32 id = 1;
}
```

### 2. HTTP/2

gRPC uses HTTP/2, which supports:

- Multiplexing (multiple calls over one connection)
- Header compression
- Bi-directional streaming
- Low latency

## 4. Types of gRPC Calls

gRPC supports **4 communication patterns**:

### Unary (Request → Response)

Like REST

```plaintext
Client → Server → Client
```

### Server Streaming

```plaintext
Client → Server → (multiple responses)
```

### Client Streaming

```plaintext
(multiple requests) → Server → Response
```

### Bi-directional Streaming

```plaintext
Client ↔ Server (both stream continuously)
```

## 5. gRPC vs REST (Quick Comparison)

| Feature | gRPC | REST |
| --- | --- | --- |
| Protocol | HTTP/2 | HTTP/1.1 |
| Data Format | Protobuf (binary) | JSON (text) |
| Speed | Very fast | Slower |
| Streaming | Native support | Limited |
| Code Generation | Yes | No (manual) |
| Browser Support | Limited | Excellent |
| Typing | Strongly typed | Weakly typed |

## 6. When should you use gRPC?

### Best for:

- Microservices communication
- High-performance systems
- Internal APIs
- Real-time streaming
- Polyglot systems (Java, C#, Go, Python, etc.)

### Avoid when:

- Public APIs for browsers
- Simple CRUD apps
- SEO-based web apps

## 7. Languages Supported

gRPC supports many languages:

- C#
- Java
- Go
- Python
- Node.js
- C++
- PHP
- Ruby

## 8. Real-world Use Cases

- Google internal services
- Netflix internal APIs
- Kubernetes
- Cloud-native systems
- Real-time chat & telemetry systems

## 9. Simple Definition (Interview-friendly)

> **gRPC is a high-performance RPC framework that uses HTTP/2 and Protocol Buffers to enable fast, strongly-typed communication between distributed services.**


---

Original Source: https://www.mindstick.com/interview/34440/what-is-grpc

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