> ## Documentation Index
> Fetch the complete documentation index at: https://docs.loadforge.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Load Testing gRPC Services

> Guide on load testing gRPC APIs with LoadForge using Locust.

## Overview

Load testing gRPC services requires specialized clients that can serialize and send Protocol Buffer messages. With Locust and the `GrpcUser` from `locust-plugins`, you can simulate high-throughput gRPC calls and measure performance under load.

## Locust Test Script (locust.py)

```python theme={null}
# locust.py
import os
import sys
from grpc_tools import protoc
from locust import task, between
from locust_plugins.users import GrpcUser

# Inline .proto definition
proto = '''syntax = "proto3";
package helloworld;

message HelloRequest { string name = 1; }
message HelloReply { string message = 1; }

service Greeter { rpc SayHello (HelloRequest) returns (HelloReply); }
'''
# Write & compile stubs at runtime
with open('helloworld.proto', 'w') as f:
    f.write(proto)
protoc.main(['', '--proto_path=.', '--python_out=.', '--grpc_python_out=.', 'helloworld.proto'])
# Ensure current dir is importable
sys.path.insert(0, os.getcwd())
import helloworld_pb2

class HelloWorldUser(GrpcUser):
    host = "grpc.server.com:50051"
    wait_time = between(1, 3)

    @task
    def say_hello(self):
        # Prepare request
        request = helloworld_pb2.HelloRequest(name="LoadForge")
        # Call the service
        self.call(request, "/helloworld.Greeter/SayHello")
```

***

**Notes:**

* Install dependencies: `locust-plugins`, `grpcio`, and `grpcio-tools` if you wish to test locally.