Just so I'm not misleading anyone, we're not actually using Paddle ourselves. I elaborated on why we ruled it out in another comment[1].
To explain where we're coming from here, I personally learned a classic first-time entrepreneur lesson the hard way some years ago: if we're not a payments business then we should focus on what we are, not on payment mechanics.
The first time I started a B2C, I naively thought I could do better, and to be fair, I really did implement a simple, robust, flexible system that fit our needs well. But over time, even the better payment services started breaking APIs and neglecting documentation and dropping customer service standards and increasing prices, and maintaining those integrations became painful. Governments started changing their regulations and tax rules, and updating our systems to keep up with the ever-changing compliance and tax obligations become painful too. We also found that fraud and chargebacks weren't a significant problem for us, but surprisingly, churn due to unreliable card charges was unbelievably bad and could turn an otherwise healthy growth rate negative all on its own, which was not a good combination with the aforementioned drop in standards at the payment services.
What we're now looking for, in a nutshell, is a service to which we can outsource payment processing, subscription management, and all of the sales tax collection, reporting and remittance obligations. I don't want to use APIs or webhooks any more than I absolutely have to. I want to fill in correct, context-aware, all-inclusive prices on our pricing page with ideally one line of code. I want to hand our customers off smoothly to a well-designed, batteries-included sign-up flow with ideally one line of code. I want a simple notification to reach my server when a customer has paid us so we can have our systems respond accordingly, and I want simple notifications if anything has gone wrong so we can contact our customer or payment service and deal with it.
I do not want to know what the current sales tax rates are in Western Nowhere, Somecountry, and I certainly do not want to have to sign up for a government programme and file reports and remit taxes there because once upon a time we had one customer who signed up for one month and we collected 1.50 Nowheredollars in sales tax.
I do not want to have any UI on my site and therefore any code behind it for upgrading, downgrading, cancelling, refunding, retrying failed charges or sending flowers on my customer's birthday, except to the extent that we provide a simple way for a customer to indicate they want to do something and we can then hand off the mechanics to the payment service if we agree, again ideally with one line of code.
I do want a simple, effective dashboard facility on the payment service that lets me see and control all of those things (well, maybe not the flowers) and any other relevant settings if I want to, and I want it to be somebody else's problem to implement and maintain that facility.
I don't know what proportion of our revenues we'd be willing to give up for a service like that, but it would be far higher than anything we pay to any payment service today.
[1] https://news.ycombinator.com/item?id=22896600