Hi.
I was wondering what is the most up to date solution for the famous "Double spend" problem?
Is there any solution (commercial company development even..) that reduce the transaction waiting approval time?

I read lot of paper's and suggestions during the years about that but it seems that most of them was just nice academic theories , I think that each industry (Exchanges/Gambling/Miners..) adopt here own and personal solution, the most relevant thing I found for now is the Blockcypher Confidence Factor API:
https://www.blockcypher.com/dev/bitcoin/#confidence-factor

I am working on something of my own for this :
https://riders.io/

Although that as a "personal" Bitcoin user this problem has never bothered me at all, I really trust the network, even with a low fees,
But as a business I believe its a total different story.

Thank you.