Duo Security vs Security Monkey: What are the differences?

What is Duo Security? Verifies the identity of your users with two-factor authentication. In order to trust that your users are who they say they are, we verify their identity with an easy-to-use two-factor authentication solution, while giving you the ability to enforce stronger user access policies.

What is Security Monkey? Monitors AWS and GCP accounts for policy changes. Security Monkey monitors your AWS and GCP accounts for policy changes and alerts on insecure configurations. Support is available for OpenStack public and private clouds. Security Monkey can also watch and monitor your GitHub organizations, teams, and repositories.

Duo Security and Security Monkey can be categorized as "Security" tools.

Security Monkey is an open source tool with 3.67K GitHub stars and 695 GitHub forks. Here's a link to Security Monkey's open source repository on GitHub.