eIDAS Certificates, PSD2, FIDO2 Passkeys & Everything at Once: eBay's Identity Journey in a Nutshell

eBay is a global marketplace that empowers hundreds of millions of buyers and sellers in more than 190 markets around the world, trading articles worth around 90 billion dollars every year. We provide new financial services to our sellers, such as keeping funds in the users' accounts for reusing them on eBay to purchase items or to buy shipping labels. In order to secure the accounts of our European sellers and to be compliant with the PSD2 regulation, eBay requires sellers in the EU and UK to use two-factor authentication on our marketplace. This talk describes the journey of eBay offering various two-factor authentications to our millions of users. In particular, eBay was among the first large tech companies offering FIDO2 passkey authentication. We also authenticate access to regulated APIs via eIDAS certificates for licensed third-party providers, as well as protect other sensitive APIs via digital signatures over the payload.