Is your Python web framework really the performance bottleneck?

The blog post explores the impact of Python web frameworks' performance on real-world applications, using FastAPI and the observability platform Pydantic Logfire to analyze where time is spent during a web request. It sets up an experiment by creating a dummy POST endpoint in FastAPI that validates data, performs a SQL query, and returns the body unchanged. By profiling both heavy and light payloads, the study reveals that most processing time is consumed by data validation and database queries, rather than the framework itself. The experiment shows that FastAPI's overhead is minimal compared to the actual application logic, suggesting that the framework is rarely the bottleneck in web applications. It emphasizes the importance of using observability tools to profile applications and identify real bottlenecks, rather than switching to a supposedly faster framework.