I'm not sure why an ad that only tells its readership "it's too complex, just use our product" was posted here.<p>While I'm new to this field myself, the standard score[1] and interquartile range[2] algorithms can be utilized for this purpose, where the underlying calculations use a "streaming" algorithm eliminating the need for storage, such as [3].<p>I recently used some of this to monitor abnormally high request times for an application at my workplace.<p>[1] <a href="https://en.wikipedia.org/wiki/Standard_score" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Standard_score</a><p>[2] <a href="https://en.wikipedia.org/wiki/Interquartile_range" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Interquartile_range</a><p>[3] <a href="https://nestedsoftware.com/2018/03/27/calculating-standard-deviation-on-streaming-data-253l.23919.html" rel="nofollow noreferrer">https://nestedsoftware.com/2018/03/27/calculating-standard-d...</a>