Table of contents

FastAPI performance tuning

FastAPI is a great, high performance web framework but far from perfect. This document is intended to provide some tips and ideas to get the most out of it

Fastapi Middleware performance tuning

Fastapi JSON response classes comparison

Gunicorn workers and threads

Nginx in front of FastAPI

Connection keepalive

Stay tuned for new ideas:

Sync / async API endpoints

Connection pool size of external resources

FastAPI application profiling

Arbitrary place of code

Profiling middleware

Test environment

All the tests were run on GitHub Actions
Application is built into a container, you can build it like this:
```
docker-compose build
```

The container has two CPU cores allocated in order to preserve resource for the test client:

app:
  container_name: fastapi-performance-optimization
  build:
    context: app_files
    dockerfile: Dockerfile
  image: fastapi-performance-optimization:latest
  cpus: 2
  restart: always

All the tests were run with the same ab tool configuration available here
- ab config: ab -q -c 100 -n 1000 -T 'application/json' ...
All tests were run 3 times and average has been calculated
Before test run the container has been pre-warmed with small amount of queries, result didn’t count in the measurement
Versions used for these measurements is in the Dockerfile

Interested in re-running the tests in your environment?

git clone git@github.com:KissPeter/fastapi-performance-optimization.git
pip3 install -r test_files/requirements.txt 
pytest -vv -rP test_files/