BJAK

Machine learning engineer in applied AI

In short

This role builds and improves machine learning models for classification, ranking, retrieval and personalization, for a company developing an agent-first, AI-native mobile communication app. It requires hands-on production ML experience, strong foundations in neural architectures, and the ability to balance model quality, latency, cost and reliability. The job is hybrid, based in London, at the middle (mid) seniority level.

About the role
There are over 5 billion users using basic applications today such as email, notes, tasks, calendar and they're not AI-native. Our mission is to build proactive applications for anyone in the world, who are not used to complex prompting. We aim to bring intelligence to conversations, errands, organising and workflows, with minimal to no prompting. Our first application is an agent-first mobile communication app.
Responsibilities
•Build and improve ML models for classification, ranking, retrieval and personalization.
•Develop efficient classifiers and optimize model accuracy, precision, latency and cost.
•Improve search relevance and context retrieval using embeddings, hybrid search and reranking.
•Build personalization models that learn from user behavior while respecting privacy.
•Develop evaluation pipelines, labeled datasets and metrics to measure model quality.
•Fine-tune and adapt existing models when supported by sufficient data.
•Build and maintain ML training, inference and deployment pipelines.
•Debug production issues, monitor model performance and ship improvements based on real-world feedback.
Requirements
•Strong foundations in machine learning and modern neural architectures.
•Hands-on experience building and deploying ML models in production.
•Experience in classification, ranking, retrieval, recommendation systems or personalization.
•Understanding of model evaluation, experimentation and performance metrics.
•Comfortable writing production-quality code and working with real-world datasets.
•Able to balance model quality, latency, cost and reliability.
•Strong ownership, problem-solving skills
Conditions
No conditions stated in the vacancy.

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