Act vs Auth0

act is an open-source command-line tool that runs GitHub Actions workflows locally using Docker containers. It reads workflow files from .github/workflows/ and executes them with environment variables and filesystem configurations matching GitHub's hosted runners. The tool enables fast local feedback on workflow changes without requiring commits and pushes to a remote repository.

Auth0 is an identity platform that provides authentication and authorization services for applications. Now part of Okta, it offers features including universal login, multi-factor authentication, social connections, and machine-to-machine authentication with support for multiple identity protocols.