It was built by an awesome team (mostly Ukrainian) called Tapforce: https://www.tapforce.com/

Here's a story about them that will knock your socks off: https://parsnip.substack.com/p/engineering-plot-twist

And, here's another one: https://www.linkedin.com/posts/mizzao_my-hands-are-trembling...

If you need work like this, hire them. They will blow your mind.