Instagram has successfully scaled its recommendation system to include over 1000 ML models while maintaining quality and reliability.The algorithm involves multiple layers of ranking funnels, constant experimentation, and a large number of models serving user traffic.Challenges in scaling included infra maturity lagging behind, slow model launches, and lack of consistent model quality definitions.Solutions implemented included a model registry, automated model launch flow, and defining model stability metrics for all models.The model registry streamlined model importance and business function information, improving operational response efficiency.Implementing criticality levels based on incident severity and automation tools for launch processes enhanced productivity and reliability.Model stability metrics were introduced to measure prediction accuracy, addressing issues faster and leading to higher-quality recommendations.Lessons learned included the importance of infra understanding, enabling rapid model iteration, and ensuring reliability considers model quality.Building robust tools and processes has not only improved operations but also empowered colleagues to drive innovation and growth.The focus on quality and collaboration has been instrumental in Instagram's successful journey of scaling its recommendation system.