The document compares REST and gRPC approaches to building APIs. It notes that while REST uses JSON over HTTP, gRPC uses protocol buffers over HTTP/2, allowing for benefits like binary encoding, multiplexing, and simpler parsing. An example shows a character request is 205 characters in JSON but only 44 bytes in protocol buffers. gRPC is also said to allow lower latency, better CPU utilization, and server push capabilities compared to REST for real-time use cases.

1. gRPC
Dharshana Ratnayake
Clearpoint

2. History of middleware
CORBA/RMI -> SOAP -> REST -> gRPC

3. REST
Application
Transport
Internet
Character
UUID id
Vector location
State state
UUID
Vector
x
y
z
State
ALIVE
DEAD
"characterRequest": {
"character": {
"id": "uuid",
"location": {
"x": 1234567890
"y": 1234567890
"z": 1234567890
}
"state": "ALIVE"
}
}
POST /index.html HTTP/1.1
Host: www.example.com
Content-Type
body{}
TCP
IP v4/v6

4. So what’s wrong with JSON over
HTTP
• Text not binary
• No multiplexing
• Needs something like swagger.
• GET, POST, DELETE, CREATE…. But what
else?
• Can see hacks appearing

5. REST vs gRPC
JSON
HTTP
Protocol Buffer
HTTP2

6. REST vs gRPC
"characterRequest": {
"character": {
"id": "13945de2-9743-4688-a88a-81002f311bc2",
"location": {
"x": 1234567890
"y": 1234567890
"z": 1234567890
}
"state": "ALIVE"
}
}
205 characters
205+bytes
1: {
1: {
1: "16 bytes",
2: {
1: 4 bytes
2: 4 bytes
3: 4 bytes
}
3: 1 byte
}
}
44+bytes
● What about 1000 messages per second
● Simpler parsing
● Better CPU utilisation

7. So, let’s write some code

8. Let’s look at some metrics
• Results of running against google compute
engine
• 3000ms vs 2700ms (post warm up)
• But wait.. We don’t have to play tennis

9. gRPC streaming example

10. Real world use case
● Naive approach 6 second lag
● UDP too much packet loss
● gRPC 150ms latancy
● Able to do server push

11. thanks
● http://www.grpc.io/
● https://github.com/darthShana
● Ray Tsang
● Able to do server push