TOTPRadius is described as 'A simple and cost-effective way to provide secure, policy-compliant and user-friendly on-premises two-factor authentication solution with self-enrollment'. There are more than 25 alternatives to TOTPRadius for a variety of platforms, including Online / Web-based, Self-Hosted solutions, SaaS, Windows and Linux. The best alternative is Keycloak, which is both free and Open Source. Other great apps like TOTPRadius are Auth0 (Freemium), FreeIPA (Free, Open Source), LoginRadius (Paid) and FusionAuth (Paid).
FreeRADIUS is responsible for authenticating one third of all users on the Internet. Welcome to the FreeRADIUS project, the open source implementation of RADIUS, an IETF protocol for AAA (Authorisation, Authentication, and Accounting).
Gigya is one of the leading social choice for websites, integrating online businesses with the top social networks such as Facebook, Twitter and LinkedIn and consolidating the most powerful social features in a single solution.
DID is the simplest way to add superior authentication to your website. Most of us have too many passwords and we don't like using them. Users not wanting to remember the details of another account is a reason for many failed sign ups particularly for smaller websites.
JustAuthenticateMe offers a simple authentication-as-a-service for your web apps. It uses magic links in emails as a way to verify identity so that neither you nor your users have to worry about passwords.