Senior Data Scientist (f/m/d)

Moss; Greater London; Hybrid; GBP 110,000 - 160,000; Full time

Benefits offered by this job

Equity

Learning & Development budget

Work from abroad 20 days

Friday demos

Job summary

Moss is expanding its Data & AI team and seeks a senior/lead contributor with hands-on LLM app/agent experience. You will own end-to-end LLM/ML initiatives—framing problems, modeling, evaluating, deploying, and iterating to improve core workflows like invoice understanding and reconciliation.

You will work with Platform/Data Eng to productionize models, ensure monitoring and scalability, and drive impact across Moss’s fintech product suite. Equity is part of the compensation package.

Qualifications

• 5–10+ years in applied ML with production ownership of shipping models/systems.
• Hands-on LLM app/agent experience (tool use/function calling, RAG, structured outputs, guardrails) in production.
• Strong Python + ML stack (e.g., scikit-learn, XGBoost/LightGBM, PyTorch/TF) and solid experiment/evaluation skills.

Responsibilities

• Own LLM/ML pipelines for extraction, classification, anomaly detection, and recommendations.
• Define evaluation & monitoring: gold sets, automated tests, robustness checks, SLAs, and cost/latency tracking.
• Productionize with Platform/Data Eng: bring your models live and iterate/improve until they are adopted by your stakeholders

Skills

LLM apps/agents

Python

ML stack

Experimentation

Production ML

Problem framing

Tools

PyTorch

scikit-learn

XGBoost

LightGBM

Docker

Kubernetes

SQL

Job description

At Moss, we give finance professionals the power to automate their day‑to‑day and make forward‑thinking decisions.

Our culture is what makes that possible: we play to win, we obsess over quality, and we win as One Moss, and it works. Moss closed a €35 million Series C in August 2026, crossing a €1 billion valuation, and became one of Europe's fintech unicorns. Join us for what's next.

We’re expanding our Data & AI team and looking for a senior/lead contributor who has hands‑on LLM app/agent experience and is fluent in classical ML. You’ll own end‑to‑end LLM/ML initiatives – from problem framing and modeling to evaluation, deployment, and iteration – directly improving core product workflows (invoice understanding, approval matching, reconciliation, anomaly detection, and user‑assist).

Your Responsibilities

• Own LLM/ML pipelines for extraction, classification, anomaly detection, and recommendations.
• Define evaluation & monitoring: gold sets, automated tests, robustness checks, SLAs, and cost/latency tracking.
• Productionize with Platform/Data Eng: bring your models live and iterate/improve until they are adopted by your stakeholders

About You

• 5-10+ years in applied ML with production ownership of shipping models/systems.
• Hands‑on LLM app/agent experience (tool use/function calling, RAG, structured outputs, guardrails) in production.
• Strong Python + ML stack (e.g., scikit‑learn, XGBoost/LightGBM, PyTorch/TF) and solid experiment/evaluation skills.
• Strategic Problem Solver: You approach ambiguous problems by deeply understanding business context and framing data science solutions that drive meaningful outcomes. You rigorously validate assumptions, identify root causes, and prioritize solving the right problem before building.
• End‑to‑End Executor: You independently own projects from ideation to production, balancing model performance with engineering realities. You ensure solutions are scalable, monitored, and maintained with thoughtful evaluation, deployment, and iteration strategies

About Moss

Moss is the Finance AI platform for Europe’s mid‑sized businesses, giving companies real‑time visibility and full control over their spend. By automating card issuing, invoice management and expenses, Moss simplifies financial workflows and frees finance and accounting teams from manual, administrative work.

Founded in Berlin and used by more than 10,000 businesses including Flink, Schufa, n8n and Auto1, Moss has raised €220+ million to date and operates in Germany, the Netherlands, the UK and further EU markets. In August 2026, Moss closed a €35 million Series C led by Portage, crossing a €1 billion valuation and becoming one of Europe’s newest fintech unicorns. Moss is backed by investors including Valar Ventures, Tiger Global, Global Founders Capital, Cherry Ventures, A-Star.

What else to expect

• Top‑of‑market compensation package, including equity.
• Our vibrant offices are at the heart of our culture, where in‑person time fuels collaboration and connection over weekly breakfasts and Friday demos.
• Additional benefits include: 20 days “work from abroad”, 600EUR/GBP Learning & Development Budget, and other local benefits.

Unless stated otherwise, benefits apply to full‑time positions (interns and working students receive a tailored package).

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