Proctor by Indeed is an open-source feature flagging tool developed by Indeed's engineering team. It facilitates progressive delivery and experimentation by allowing developers to enable or disable features across their user base without deploying new code. This tool supports phased rollouts, A/B testing, and detailed targeting to specific user groups, enhancing control over application behavior in production. Proctor is designed to be lightweight, scalable, and suitable for complex environments, providing robust capabilities for managing feature flags effectively.