Data Scientist in London

About Harmonic Security

Harmonic Security lets teams adopt AI tools safely by protecting sensitive data in real time with minimal effort. It gives enterprises full control and stops leaks so that their teams can innovate confidently. We are led by cybersecurity experts and backed by top investors including N47, Ten Eleven Ventures, and In-Q-Tel. We’ve achieved early traction and strong product-market fit with a world-class team, and we’re now focused on scaling the data foundations that power our product, analytics, and machine learning. This is an opportunity to join early, take real ownership of core data systems, and help define how data is modeled, moved, and trusted in a new category of AI security.

About the Team

Our Product Delivery team is the engine that turns vision into impact. We ship early and often, getting valuable features into the hands of customers quickly and iterating from there. We work in the open by default, sharing progress and ideas, and we trust each other to own outcomes. We’re a small but mighty crew where every person plays a critical role and we’re committed to using AI to work smarter and faster.

About the Role

As our Data Scientist, you will be a critical member of our team, laying the groundwork for groundbreaking advancements in secure Generative AI adoption. Your expertise will be instrumental in building and continuously improving the detection models at the heart of our product, from curating high-quality training datasets to tuning production models informed by real-world customer feedback.

What You’ll Do

• Working collaboratively to design and curate comprehensive datasets tailored to train and fine-tune our sensitive data detection models.
• Your analytical rigour will be key to developing new detection models, from defining what a new sensitive data category looks like through to building, validating, and shipping a production-ready model.
• You will also drive continuous improvement of our existing model suite, using performance dashboards and direct customer feedback to prioritise retunes and sharpen detection accuracy.
• You will stay abreast of the latest data science trends and techniques, continuously seeking ways to optimise models and datasets to enhance model performance.
• You will collaborate effectively with engineers and security teams, fostering clear communication around data needs and ensuring seamless integration with our security solutions.

You will be directly contributing to the development of groundbreaking technology that empowers secure Generative AI adoption within enterprises.

This role is a great fit for someone with:

• Models running in production and integrated into a live product.
• A proven track record of building and managing high-quality datasets.
• A desire to work in a fast-paced, innovative environment.
• A product driven mindset with a focus on incremental delivery.
• Expert knowledge of Python and relevant libraries.
• Knowledge of natural language processing (NLP) techniques.
• Excellent communication and collaboration skills.

Bonus points if you have:

• Experience building systems that utilise generative AI models.
• Experience working in the data security domain.
• Strong understanding of classification approaches and models.
• Strong understanding of data categorisation techniques and taxonomies.
• Been in front of customers and/or end-users to build a complete understanding of the problem domain.
• Experience with cloud platforms (e.g., AWS, Azure, GCP).

Why Join Us

This isn’t just a job; it’s an opportunity to be part of a team that is redefining cybersecurity. We believe today’s talent is tomorrow’s success, and we’re committed to creating an environment where you can do the best work of your life.

• Competitive pay and meaningful equity with a direct stake in Harmonic’s success.
• Comprehensive benefits, pension plan, generous PTO, and flexible hybrid work.
• A small, passionate team that values transparency, creativity, and learning.
• Thoughtful leadership that cares deeply about growth, impact, and people.
• Annual global offsites (past trips include Lisbon and Nashville).
• The chance to directly shape both our product and our culture as we build a category-defining company.

Harmonic’s Core Values

• Flourish in the Unknown: We relish being thrown into new, unfamiliar situations that require initiative and rapid decision-making. We orient ourselves quickly and deliver results with minimal guidance.
• Never Full: We never hesitate to raise our hands and take on challenges to assist those in need. We hunger for opportunities to learn and do more.
• Perfect Harmony: We have a genuine willingness to assist and support one another to create cohesion and unity. We foster success through collaboration and honest sharing of feedback and ideas, enabling everyone to grow and produce their best work.