Beeswarm · Diagram Design
A hundred and thirty-eight per-request latency samples for one checkout endpoint, one dot per request on a shared linear axis from zero. The median sits near 105 ms and looks perfectly healthy; the story is the three requests past 380 ms, because the p99 is what a customer at the wrong moment actually experiences.
Read the swarm, not the middle
req-4c1f took 431 ms — four times the median — and it is one of three requests past 380 ms in a five-minute window. At this rate, roughly one checkout in fifty gets a visibly slow page, which is exactly the reading a single averaged number would have hidden.
One dot = one request
No binning, no averaging: each request is its own dot at its exact value. Density reads as thickness — the swarm bulges where requests crowd — so the shape of the distribution and its outliers arrive in one glance.
Packing, not a value
Dots dodge up and down only so they do not overlap; the offset is greedy packing at a fixed pitch and carries no meaning. A dot is never moved along the value axis to make room — crowding is data.