Senior Backend Engineer - AI/ML and Social Feed Systems

About the Role We are building a next-generation AI-driven social platform that combines high-engagement short-form video feeds with intelligent product recommendations and content discovery. We are seeking a Senior Backend Engineer – AI/ML & Social Feed Systems to design and build the backend infrastructure powering our social feed, recommendation, and discovery experiences. This role sits at the intersection of Node.js/TypeScript backend engineering, Python-based ML pipelines, GCP cloud infrastructure, and AI-powered recommendation systems. You will have significant ownership of high-throughput, low-latency backend services and work closely with the founding team and mobile engineering team to build a scalable platform capable of supporting rapid growth. Key Responsibilities Design, develop, and optimize high-throughput social feed infrastructure using Node.js, TypeScript, and microservices.Build fan-out services, caching strategies, data aggregation, and low-latency APIs for personalized social feeds.Develop and integrate machine learning and recommendation pipelines using Python.Implement recommendation capabilities including candidate generation, ranking, embeddings, personalization, and content filtering.Integrate GCP AI services, including Vertex AI and Vision/Video APIs, for content analysis, metadata extraction, video tagging, and personalization.Design and optimize cloud-native services on Google Cloud Platform (GCP) for scalability, reliability, and performance.Work with Redis, PostgreSQL, and vector databases to support high-performance feed delivery and recommendation workloads.Build and maintain integrations with Pinecone, Weaviate, GCP Vector Search, or similar vector database technologies.Develop asynchronous and event-driven backend workflows where appropriate.Collaborate with mobile engineers working with Expo / React Native to ensure efficient API integration and smooth feed experiences.Participate in architecture decisions, code reviews, performance optimization, testing, and production troubleshooting.Work in a fast-moving engineering environment using Linear, Cursor AI, and modern AI-assisted development workflows.Partner directly with the founder and engineering team to define and deliver critical platform capabilities.Required Qualifications 5+ years of professional backend engineering experience.Strong hands-on experience with Node.js, TypeScript, and JavaScript.Experience designing and building high-concurrency, high-throughput backend services and APIs.Hands-on experience with Python for ML pipelines, data processing, model integration, or recommendation systems.Experience building or scaling social feeds, recommendation engines, content discovery systems, or personalization platforms.Strong experience with Google Cloud Platform (GCP).Experience with services such as Cloud Run, GKE, Cloud Functions, Pub/Sub, Cloud Storage, BigQuery, and/or Vertex AI.Strong knowledge of Redis for caching and high-performance data access.Experience with relational databases, particularly PostgreSQL.Experience with vector databases or vector search technologies, such as Pinecone, Weaviate, or GCP Vector Search.Understanding of distributed systems, microservices, API design, scalability, and performance optimization.Ability to work effectively in a fast-paced, startup-oriented environment.Preferred Qualifications Experience with computer vision, multimodal AI, or video understanding.Experience integrating AI models for video tagging, product recognition, metadata extraction, or content classification.Experience developing backend APIs consumed by React Native / Expo applications.Experience working on large-scale consumer or social platforms.Experience with recommendation systems, ranking algorithms, embeddings, and personalization.Experience working in a high-velocity startup environment.Familiarity with AI-assisted development tools such as Cursor AI.Technology Stack Backend: Node.js, TypeScript, JavaScript Machine Learning/Data: Python, ML pipelines, recommendation systems, embeddings Cloud: Google Cloud Platform, Cloud Run, GKE, Cloud Functions, Pub/Sub, BigQuery, Vertex AI Databases: PostgreSQL, Redis, Vector Databases AI/ML: Vertex AI, Vision/Video APIs, Computer Vision, Multimodal AI Mobile Integration: Expo, React Native Development Tools: Cursor AI, Linear Work Model & Location Preferred: Hybrid / In-Office in El Segundo, CA Remote: Exceptional candidates located in North America or Latin America who can work effectively within PST-aligned working hours will be considered. Engagement Options Full-TimeContractTrial-to-HireDirect HireWhy Join Us? This is an opportunity to take ownership of a core platform component from the ground up. You will directly influence the architecture and scalability of an AI-powered social platform, working across backend engineering, machine learning, cloud infrastructure, and personalized content discovery. If you enjoy solving challenging distributed-systems problems and building products where backend engineering and AI/ML directly impact user engagement, we would love to hear from you.