For the past few months I've been working on a payment system for Stellar. I was initially inspired by Brainblocks (for nano) and was disappointed that Stellar didn't have anything similar.
First I built a brainblocks clone for Stellar but wasn't happy with it. An ideal payment solution should not rely on the user entering the correct address, and sending the correct amount with a correct memo. The user should just be able to sign off on a transaction and have it happen!
I then started looking at Stripe Checkout and how they accept payments. Warp checkout ended up being very similar.
Warp checkout takes a different approach to payments compared to the solutions I've seen so far. I generate an unsigned transaction from the customer to the merchant for the correct amount. The customer just has to sign it. They can do so using their private key within warp checkout, or they can sign using the Stellar Laboratory transaction signer.
In the future, I'd like to see wallets that support signing pre-existing transactions. This way instead of entering their private key, a user can just scan a QR code on their phone and view/sign the transaction securely from their wallet app.
Check it out and let me know what you think: https://warp.st