It's not entirely clear on their website, but I assume the full software is at https://github.com/frappe/erpnext, and they have a model similar to Sentry?

Word of advice: stay away from Erpnext, don't get fooled by the apparent "clean" interface.

They might have some good conceptual ideas, but the implementation is horrific, their ops/delivery infrastructure a shitshow if even there's one, bugs all over the place and a product management that basically says yes to everything and finishes nothing.

They are in part victims of their own success, but just look at their Github issues page.