Methods, apparatus and computer programs for authorizing transactions are described. A server system receives, from a first computing device, verification information relating to a verification process for verifying a user associated with the first computing device. A verification status associated with the user is set in a memory of the server system, based on the verification information. The server system receives an authorization request for a payment transaction from a payment terminal, the request including an identifier associated with the user, and having been provided to the payment terminal by a payment device different from the first computing device. Responsive to receipt of the authorization request, the verification status associated with the user is identified, and a determination as to whether to authorize the payment transaction is made at least partly on the basis of the identified verification status.