I was completely wrong. I didn't know my clients and my market. This is the exact definition of operating mainly on assumptions. I lost at least 18 months, since I could have find this out way sooner.
I'm sorry to hear you were not successful, that REALLY sucks to spend all that time and not feel good about it.
It sounds like maybe you waited too long to attempt to sell anything? That's what MVPs are for, to give you feedback to see which of your early assumptions were correct. Ditch the incorrect ones, focus on the correct ones and get better at making assumptions and grow your business organically, based on a positive feedback loop.
Then I found ont the real truth:
- Merchants won't find your website to buy your amazing product, you need to meet them physically (that can seems obvious but it was not the case for me at that time)
- Merchants don't care about you or your product. They won't listen to you in deep, except if you have specific social skills (I don't). Every day someone enters in their shop trying to sell them something. If you're not psychologically ready to hear "I don't care" or "is it free?" 9 times on 10, then you can not do that for a very long time.
- Independant merchants, generally speaking, don't have any marketing skills. What seems obvious for you is not for them. For example, they don't see the powerfulness of getting emails and consuming habits of their own customers. Plus, I'd say 2/3 of them were really suspicious about technology in general.
So what was hard here was not to make a product that have intrinsic value for merchants, but to teach merchants what this value is.
The real need to succeed in this project is absolutely not tech, it's to know the market, and how to convince merchants.
That said, all of this would be as expected, even for a great product, with product-market fit.
Selling is hard, you have to find the right niche of customers, references, and not everyone will love it right away.
Great lesson that you will take with you on the next run.
Selling is hard, and becomes close to impossible if like me, you don't know your target, and on top of that, you're socially anxious to talk to strangers and get a "no" as answer.
Client prospection requires specific skills I don't have and I'll probably never get.
Sometimes we (solo-dev people) need to be more humble and accept we can not do everything well. Or as an alternative, we need to find project ideas that suit our skills better (B2C would probably have been easier for me than B2B).
Did you try to look for a sales partner?
What are you working on now?
Hopefully you are back on your feet again. We must learn from our failures and move on.