Techniques are disclosed for providing and/or implementing utilizing declarative techniques for transaction-specific authentication. Certain techniques are disclosed herein that enable transaction signing using modular authentication via declarative requests from applications. An application can declaratively specify one or more transaction factor values to be used in an authentication, and the authentication, using a transaction-signed one-time password, can be directed by an access manager module without further involvement of the application. Upon a successful or non-successful authentication, the access manager module can provide the result back to the application. Accordingly, an authentication process specific to (and valid only for) a particular transaction can be performed without direct involvement of the application and without application-centric knowledge required by the access manager module.