Senior ML Engineer (Social Media - Recommendation Systems)

!Individual freelancers ONLY. No agencies or outsourced firms.! We are looking for a [Senior Machine Learning Engineer] to own and evolve the recommendation engine for a high-traffic social media platform. You will not just be "tuning models"; you will be responsible for the entire technical roadmap, from designing large-scale feature pipelines to optimizing real-time inference services. 【Key Responsibilities】 ~Design and implement end-to-end recommendation pipelines (Candidate Generation → Ranking → Re-ranking). ~Build and maintain robust feature engineering pipelines using Apache Spark and Delta Lake. ~Develop and deploy high-performance ML models (Ranking/Retrieval) that impact core product metrics. ~Optimize model training and inference efficiency to handle billions of user signals. ~Navigate through "noise" in large datasets and implement automated monitoring/retraining systems. 【Requirements】 ~5+ years of professional experience in Machine Learning, specifically in Recommendation Systems or Ads Ranking for social media/consumer platforms. ~Expertise in Python, SQL, and C++ for high-performance computing. ~Proven experience with big data tools: Spark, Delta Lake, or Flink. ~Deep understanding of multi-stage ranking architectures and A/B testing methodologies. ~Self-starter mindset: Ability to lead technical projects with minimal supervision in a fully remote environment. ~Mandarin Chinese proficiency is a plus. *Project Type: Ongoing project *Location: Fully Remote *Payment: Hourly (Please submit your competitive hourly rate based on your expertise)