Consuming services online is an exponentially growing trend within different industries. A robust online authentication solution to these services is a critical requirement for establishing trust between end users and service providers. Currently, the shortcomings of password based authentication solutions are well recognized. Hence, many alternative strong authentication solutions are being adopted. However, the latter create a siloed model where each service provider dictates a different method (OTP, SMS...) to end users. To resolve these challenges, considerable efforts are being deployed by both academia and industry. However, assessing these efforts is not a trivial task. This paper provides a framework of a well-motivated set of attributes, for categorizing and assessing online authentication solutions. Based on this framework, two main approaches for online authentication are identified and exemplified: LUCIDMAN and FIDO. The results of this research are anticipated to make the navigation of the online authentication solutions space more systematic, and facilitate knowledge transfer between all stakeholders.