Kayako Fusion -

Kayako Fusion was the Linux of helpdesks. It was powerful, customizable, and free (as in beer, sort of)—but you had to want to tinker with it.

: By encouraging the use of a knowledge base, Fusion helped companies shift their focus from reactive support to proactive education. The Legacy of Fusion kayako fusion

You bought it once. You installed it on your hardware. The data was 100% yours. No per-agent monthly fees eating your budget. For a bootstrapped startup in 2013, buying Kayako was a "capital expense" that felt cheaper than a monthly subscription. Kayako Fusion was the Linux of helpdesks