Senior Machine Learning Scientist

NLP PEOPLE; United States; Remote; USD 120,000 - 150,000; Full time

Benefits offered by this job

Monthly Health & Wellness budget

Annual Learning and Development budget

Flexible working in a choice-first environment

Work From Home Allowance

25 Holiday Days + local bank holidays

Your birthday off

Enhanced Family Leave

Optional Healthcare Plan

Life & income protection

Employee Assistance Programme

Opportunity to share in the company’s success

Job summary

NLP PEOPLE is seeking a Senior Machine Learning Scientist to drive innovation in AI technologies. This role involves training and evaluating ML models for customer feedback, designing evaluation frameworks, and collaborating with cross-functional teams to deliver practical ML solutions. Ideal candidates will have deep knowledge of transformer architectures, strong PyTorch skills, and extensive experience with large-scale text data. A MSc/PhD in a related field is preferred, as well as excellent communication skills and a proactive approach to solving problems.

Qualifications

• Experience with PyTorch, able to write custom training loops and modify model architectures.
• Extensive experience working with large-scale text data including classification and search.
• Excellent communication skills to explain technical concepts clearly.

Responsibilities

• Train, evaluate, and iterate on ML models for customer feedback.
• Build and maintain LLM-powered features.
• Design robust evaluation frameworks for non-deterministic systems.
• Collaborate with Product teams to translate business needs into ML solutions.
• Mentor team members and integrate advances from research.

Skills

Deep working knowledge of transformer architectures

Strong PyTorch skills

Experience with large-scale, messy real-world text data

Experience in instruction fine-tuning and serving language models

Solid grounding in classical ML and statistics

Practical experience building with GenAI

Excellent communication skills

Technical curiosity and keen interest in AI

High ownership and initiative

Education

MSc/PhD in Computer Science or related field

Job description

Senior Machine Learning Scientist

Location: UK or Poland (Remote or Hybrid)

Compensation: Dependent on experience

Perks

• Monthly Health & Wellness budget, increasing with length of service
• Annual Learning and Development budget, increasing with length of service
• Flexible working in a choice-first environment – we trust the way you want to work!
• Work From Home Allowance
• 25 Holiday Days + local bank holidays, plus an extra day for every year of service
• Your birthday off
• Enhanced Family Leave (UK Only), Fertility Leave, and Neonatal Leave
• Optional Healthcare Plan
• Life & income protection (Location dependent)
• Employee Assistance Programme (UK Only)
• Opportunity to share in the company’s success through options
• Dog-friendly office in London with great classes, events, and a rooftop terrace

The Role

Our mission is to help large successful brands like Uber, Amazon, Wise, HelloFresh and more put their customers at the centre of everything they do. Using best‑in‑class tech in a fast‑developing AI space, our Customer Experience Intelligence platform continuously analyses explicit and implicit feedback to enable our clients to identify what they should do next.

Key Responsibilities

• Train, evaluate and iterate on ML models and agentic systems for customer feedback, including owning custom fine‑tuning pipelines. Run experiments end‑to‑end, track results rigorously, and make clear recommendations on what to ship, iterate, or retire.
• Build and maintain LLM‑powered features: retrieval pipelines, reranking systems, insight agents, data mining agents, and automated taxonomy generation.
• Design and run robust evaluation frameworks: build test sets, define metrics, evaluate non‑deterministic systems, handle class imbalance, and automate checkpoint comparisons.
• Improve and extend semantic search and retrieval, evolving from embedding‑based approaches toward more advanced methods.
• Write production‑quality code and collaborate closely with Engineering on productionisation, model serving, data pipelines, and monitoring.
• Work with Product and Commercial teams to translate business needs into practical ML solutions, and support client evaluations and accuracy benchmarking.
• Mentor team members, review code and research, and bring relevant advances from the literature into the product.

Required Skills

• Deep working knowledge of transformer architectures.
• Strong PyTorch skills, with the ability to write custom training loops, modify model architectures, and debug issues at the tensor level. Experience with parameter‑efficient fine‑tuning techniques such as LoRA.
• Extensive experience working with large‑scale, messy real‑world text data, including classification, extraction, embeddings, re‑rankers, clustering, and search.
• Experience in instruction fine‑tuning and serving language models, familiarity with frameworks such as vLLM, DeepSpeed, or similar tools.
• Solid grounding in classical ML and statistics, and the judgement to choose simpler methods when they’re the right solution.
• Practical experience building with GenAI and agentic patterns.
• Excellent communication skills and confidence translating complex technical concepts for non‑technical audiences.
• Technical curiosity and keen interest in AI – love of experimenting to make the most of available technology.
• High ownership and initiative, with the ability to identify problems, prioritise effectively, and drive solutions forward.

Preferred Add‑On Qualifications

• MSc/PhD in Computer Science, Machine Learning, Artificial Intelligence, Data Science, Computational Linguistics or a closely related STEM field.
• Experience with reinforcement learning techniques, such as verifiable reward (RLVR).

Company

Chattermill Analytics Limited