Brilliant solution, but can anyone tell me how they avoid fraud? I just sent money to a friend, and back. It worked fast and flawlessly, as expected. Supposedly money will be posted to my account in 24-48 hours. All good there.<p>Now, how can they make sure that the email is genuine and wasn't spoofed? Sure, they can check for white-listed domains and SPF records, but still seems fairly weak process. The FAQ [1] doesn't say much either. Human validation is even worse.<p>It helps that the send receives an email confirmation with the transfer, but you may not check the email before the money is posted. I guess they're pushing the onus of the proof to the receiver -- after all to receive the money you have to have a bank account and a visa/mc debit card.<p>Whatever the security mechanism, it's a brilliantly simple solution. If it takes off, it'll quickly replace Dwalla and other micropayments.<p>[1] <a href="https://squareup.com/help/en-us/article/5144-square-cash-security" rel="nofollow">https://squareup.com/help/en-us/article/5144-square-cash-sec...</a>