Joshua Kristein

I am a Senior Full-Stack Software Engineer with nine years building scalable, AI-powered applications and distributed systems, primarily at Meta. I specialize in Python, React, Java, and PHP, and have led architecture and productionization of RAG pipelines, transformer-based integrations, real-time data processing, and high-throughput microservices to drive measurable improvements in personalization and performance.

I architected and scaled the Instagram Reels feed and semantic search, improving watch time and relevance through LLM integrations, Kafka-based exactly-once pipelines, resilient microservices, and optimized model serving. I mentor junior engineers, collaborate closely with ML and product teams, and deliver robust monitoring, testing, and CI/CD practices that reduce latency, increase uptime, and catch regressions before release.