Got $10K+ worth of work with my side project.

I started building my form builder as a side project in the month of Jan. It took more than 3 months to complete the alpha version of this builder while evaluating all other competitors. Then one day I posted here and also on reddit.
Not much traction I got, but one anonymous user from reddit DM'ed me in April month. Impressed by my work, he asked me to build something like this for freelancers. It was a freelance-client SaaS product.
On first look I neglected as I find it suspicious as the client is completely anonymous (no social media, online presence) and then after few days I told him a minimum $8k budget. He said ok and sent me a 1 year old design to look into. I charged him $100 for confirmation after evaluating his project and told him the final price which was $12k-$14k range.
After all this, we did a skype video call to map the project timeline, initial deposit etc.
Now finally I completed his project after 2+ months and got full payment now. Though my current side project is not getting any visitor and there is no MRR on this. I'm still in profit due to this and more to come.

This is my side project: https://minform.io

Payment proof (just in case, payment was in project milestone basis, so screenshot is of last payment ):
https://imgur.com/TlbOrnd