API Ratings: Performance
For our API ratings, we look at over 100 APIs and pull all the metrics together to give you a general feeling for the service quality for an organization’s APIs in a particular API ratings category with our patented CASC score.
Something of interest
Twitter is a good example of a performant API, topping the Social Networks category this month with a fine CASC score of 9.57 in what is a fairly competitive category, with 5 of the 10 APIs having a CASC score of over 9.00 and only one API being in the Amber Zone. 
Twitter has a 100% pass rate and is third fastest with the lowest number of outliers, so this is a reliable API. Here we see the latency for the Twitter User Profile Fetch endpoint. It’s pretty stable within the 250-500 ms range with just one – and very obvious outlier (interestingly with the second slowest call for the month very close to it). This is how and endpoint should behave. 
It’s interesting to compare the 18 November outlier with a typical call. The call was made from Azure US west, so nowhere exotic. The rate-determining step was the HTTPS handshake, which took 18,291 ms. The Download time was pretty slow too at 1258 ms. This looks like a network issue. For Twitter, these issues happen so rarely that it might just be the kind of one-off network glitch you get from time to time. It could be there’s much to be done about and little point in worrying about such a rare occurrence. 
By comparison, our typical results is from somewhere exotic, OpenHost Auckland in New Zealand, but has a HTTPS handshake of 86 ms and a Download Time of 0 ms. Much more like what Twitter usually delivers! Note that the processing time is 227 ms versus just 86 ms for the outlier, so there’s always a degree to which there is some extra speed that you can squeeze out (and you can’t do anything about the size of the Earth or the speed of light yet). 
API Ratings: Overall Quality
November 2020
Category
Organization
CASC score
Corporate Infrastructure
Pivotal Tracker
9.40
COVID-19
ECDC