FastAPI

Many FastAPI users use HTTPX as a modern and very fast HTTP client, which also supports async/await syntax like FastAPI does.

Here is an example of how HTTPX can be used in FastAPI.

from fastapi import FastAPI
from httpx import AsyncClient
from httpx import Limits

app = FastAPI()
client = AsyncClient(limits=Limits(max_connections=1000))

@app.get("/")
async def main():
    response = await client.get('https://www.encode.io')
    return response.status_code

Now let's do some load testing using the popular load testing tool Locust.

Here are the test results:

Despite the fact that we use async/await, we got only ±70 RPS.

Now let's change the httpx.AsyncClient to hishel.AsyncCacheClient and do the same tests again.

from fastapi import FastAPI
from hishel import AsyncCacheClient
from httpx import Limits

app = FastAPI()
client = AsyncCacheClient(limits=Limits(max_connections=1000))

@app.get("/")
async def main():
    response = await client.get('https://www.encode.io')
    return response.status_code

Here are the test results:

Now we have more than 365+ RPS using the power of HTTP caching.