>> These systems were no fun They are indeed no fun. And payment APIs make me want to shoot myself. Whoever writes them seems to enjoy making end developers bl

>> These systems were no fun They are indeed no fun. And payment APIs make me want to shoot myself. Whoever writes them seems to enjoy making end developers bleed from the eyeballs. But I've written my own in-house billing software three times over since 2002 when I had to write my own front-end API to a raw CC gateway and guess what the outputs meant ... it's much simpler now to deal with asynchronous payments and it's not the end of the world to manage them. The much, much bigger problem is getting your clients to pay on time. Knowing who usually pays and who's okay being late (versus who is habitually delinquent) and keeping tabs on that before you bill them again so you don't have to suddenly confront them about canceling their services. The smaller the business, the more significant a portion of time this can take up. When I started working for an ad agency in 1995, the owner had me stand outside a guy's factory next to her with a picket signs because he owed her $5000 for an ad that ran but was a month overdue. I have written backdoors into most large pieces of software I've built, in case of nonpayment; but never had to use them. I've pulled the rug out from hosting and left people's websites saying "Joe X doesn't pay his bills" after being treated badly by clients who were 6 months late paying. These things all give me a certain sense of glee but never get me paid. The best strategy I've found is calling your clients on a rotating basis and checking in to see what they need next and gently reminding them that their bill is due. I try to make this round about once a month.