One thing you could do is write a really good invoicing app that works with a decent GAAP accounting system, like LedgerSMB. If the system is ok, and the database underneath is solid, you can do the GAAP stuff without having to write a whole accounting package.
See, the thing is: creating an invoice is an 'accounting' event that needs to be thought out a bit. Like a double entry general ledger, receiving payments, proper audit trails, the inability to modify an invoice after 'posting' it, batches, periods, and other goodness.
Otherwise, you get this ugly term: embezzlement.
But kudos for opensourcing it and standing up to criticism from hecklers like me.
First there is an unspoken assumption in your post. Embezzlement can only happen when someone is handling someone else's money. In many sole proprietors, this is not the case. So for those, sure. But it's important to understand the limitations here.
But still within the core area, I think you have to accept that I would trust your books if they were kept in pencil more than I would trust books kept with software that didn't have proper controls.
I disagree, as a business should think first in the broad context of product/market fit, which is a very dynamic issue, and not all markets need the kind of depth in an accounting product you describe.
The only case where that my be true is the case where you have a sole proprietor where the owner is the only one who touches the books. As soon as you have a bookkeeper who is not the owner, or multiple owners you do need that kind of depth.
I'd bet the OP intended it for use by sole proprietors like himself, and that he never aimed to build a product for bookkeepers. There's plenty of a market for invoicing software that targets sole proprietors.
A product with as much depth would likely appeal to accountants or those that assist them directly.
I think competition was never your problem. A lack of passion for your industry/product over the long-term, is most always the high level reason people start and stop projects like this.
I spent all of my spare time for a solid nine months on this project, and you are right; I was passionate, but more about the project itself than the industry.
There was also a fear of letting this be my full time gig and not having a steady paycheck. My brick and mortar business had just closed its doors as my biggest client stopped paying people (he literally disappeared into the woods and had a class action lawsuit from many people he owed money).
I had the same happen to me, in the sense that I built a company around passion for the software project vs. the business. It really helped me see what motivations to give more and less weight to. I'd bet your next passion project is a big success.
