Mathias Hansen, co-founder of Geocodio, on how they analyze their API response times:
For the longest time, we focused on average response times. It is a quick and simple metric that you can quickly break down by API endpoint and time window. […] While measuring average response time have their place they can also be deceptive.
The problem is that outliers go unnoticed that way, so better is to use percentiles:
Using percentiles, you will be able to say: “X% of API calls have a response time of Y milliseconds or less.”
A (rather big) query to quickly generate reports like these is included in the post 🙂