An Israeli startup in the emerging B2B2C space that allows consumers to make payments through major messaging apps has completed a $6 million round of funding backed by Banco Santander, Mastercard and other investors.

PayKey, which began in 2014, is a technology provider whose downloadable keyboard lets users connect to their banks and initiate peer-to-peer payments from any social network or messaging app, including WhatsApp, Facebook Messenger or Twitter.

PayKey says its flexible technology can be branded by any bank regardless of its technology platform. For banks, integrating the technology takes place at the API — application platform interface — level and would not clash with their existing security systems.

"As consumers become increasingly comfortable conducting financial transactions on mobile through social apps, it's essential for banks to offer services that cater to these changing behavior patterns in an easy-to-use, secure way," Daniel Peled, PayKey's chief executive, said in a news release Tuesday.

Santander did not say how much it invested in the round. It has a "longstanding relationship with PayKey" and is working closely with the startup to conduct trials across Santander's markets, Mariano Belinky, managing partner of the Spanish banking giant's fintech venture capital fund, said in the release.

Belinky also said PayKey "can make payments even more accessible and integrated with consumers' digital lives" and that the bank is "actively interested in the potential to bring that value to our customer base."

PayKey won the BBVA Open Talent competition in April.

Other participants in the funding round include e.ventures, Gaby Salem of Wharton Asset Management, CommerzVentures and Digital Lenders Ventures.