Machine Learning Engineer, Ranking & Retrieval

Location: China; remote

Company

hirify.global's ActAI Engineering team is building an agent-first mobile communication application that integrates AI into everyday communication, coordination, collaboration, and workflows.

What you will do

• Develop and improve ML models for classification, retrieval, ranking, and personalization.
• Build ranking and classification models while optimizing accuracy, precision, latency, and inference cost.
• Improve search relevance and context retrieval using embeddings, hybrid search, and reranking.
• Develop personalization models from user behavior and product data.
• Build evaluation pipelines, datasets, and metrics to measure model quality and detect regressions.
• Train, fine-tune, deploy, monitor, and debug models through production ML pipelines, using evaluation results and user feedback for improvement.

Requirements

• 3+ years of machine learning engineering experience, including deploying models to production.
• Strong Python skills and experience with PyTorch or JAX.
• Solid understanding of machine learning algorithms, model training, and evaluation.
• Experience with classification, ranking, retrieval, recommendation, or personalization models.
• Experience with embeddings, vector search, or information retrieval systems.
• Experience building data pipelines, training workflows, and model inference services.
• Ability to evaluate model performance using relevant metrics and experimentation.
• Understanding of trade-offs between model accuracy, latency, computational cost, and reliability.

Nice to have

• Experience with transformer models, LLM fine-tuning, or embedding models.
• Experience with hybrid search, reranking, and retrieval evaluation.
• Experience with recommendation systems or personalization in consumer applications.
• Experience with large-scale ML training or inference infrastructure.

Culture & Benefits

• Remote full-time position based in China.
• Work on an AI-native consumer communication application designed for daily use with minimal prompting.