One of the most frequent complaints we hear from stores that use Quail (https://quailhq.com) is how much time they spend chasing up their dealers for late or missing rent payments. Quail helps them track what they're owed, but it doesn't do anything to help with collection.
After talking in detail with a couple stores, we put together a MVP automated-billing product that we're calling "Rent Robin". Right now we're pitching it as an add-on to Quail, something that sends out automatic invoices that vendors can pay online or in person, tracks late payments (and applies late fees!), nag renters with outstanding invoices and generally put rent collection on autopilot. Fellow indie hackers: think of it like Stripe Billing + Invoicing, but much more streamlined and standalone.
This month we officially launched that MVP in three stores using Quail, and it's already processed $2,600 in rent payments (earning ~$35 in processing fees) across their vendors. I'm building out a one-click integration to make it even easier for Quail stores to try out, and then I guess we'll see how it goes.