LoopPay’s digital credit card has attracted the attention of credit card titan Visa(s v), which may be just be looking for alternatives to plastic. LoopPay said on Thursday that Visa has made a strategic investment in the company of an undisclosed sum. LoopPay makes programmable keychain fobs and iPhone sleeves capable of generating a magnetic field that emulates the magnetic stripe on a credit or debit card. And point-of-sale terminal that can read it. GE’s financial arm has also made an investment in Loop, and last year the Boston startup raised at $10 million Series A round.