With size and scale comes complexity in billing and sales tax compliance—woohoo! Asana has a pretty solid stack, although we have some thoughts 💭
Asana uses Zuora as their payment subscription manager, with Stripe connected as their payment processor, and Avalara as their automated sales tax compliance tool.
We've not had the best luck with Avalara (have actually written quite publicly about how bad they are along with Transistor via a recent podcast episode), but companies like Help Scout + Motion have managed to make it work for them.
That said, even companies like Zapier are avoiding Avalara in favor of Vertex. There really aren't great solutions in this space, it's all about picking the lesser of all evils.