A computing platform may receive, from a client portal server, a request to authenticate a first user to a first user account. The computing platform may generate a first one-time passcode for a first computing device associated with the first user account and may send, to the first computing device, the first one-time passcode. The computing platform also may generate a second one-time passcode for a second computing device associated with the first user account and may send, to the second computing device, the second one-time passcode. Thereafter, the computing platform may receive first one-time passcode input and second one-time passcode input, which the computing platform may validate. Based on the validating, the computing platform may generate a validation message directing the client portal server to provide the first user with access to the first user account, which the computing platform may send to the client portal server.