While building an app with FastAPI can be reasonably straightforward, deploying and operating it might be more challenging. The whole user experience can be ruined by unexpected errors, slow responses, or even worse — downtime. AppSignal is a great tool of choice for efficiently tracking your FastAPI app's performance. It allows you to easily monitor average/95th percentile/90th percentile response times, error rates, throughput, and much more. Useful charts are available out of the box.