Data Scientist
Harmonic Security
Data Science
England, UK · London, UK
Posted on Apr 4, 2026
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.
How We Work: AI-First by Design
Harmonic exists to help enterprises adopt AI safely and at scale. We hold ourselves to the same standard. Everyone at Harmonic actively uses AI tools to do their best work, from research and writing to building processes and automating workflows. We expect every new hire to bring curiosity about AI and a willingness to use it to work smarter, faster, and more creatively. For some roles, that means tinkering and staying open to new tools. For others, it means building entirely new systems with AI at the core. We'll be clear about what we expect for each role, and we'll give you the tools and support to get there.
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'll 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
Bonus points if you have:
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.
🌱 Flourish in the Unknown
We embrace new, unfamiliar situations that require initiative and rapid decision-making. We orient ourselves quickly and deliver results with minimal guidance.
🔥 Never Full
We raise our hands, take on challenges, and assist others whenever possible. We hunger for opportunities to learn and do more.
🤝 Perfect Harmony
We support one another to create cohesion and unity. We collaborate openly, share feedback honestly, and help everyone produce their best work
We are led by cybersecurity experts and backed by top investors including N47, Ten Eleven Ventures, and In-Q-Tel.
How We Work: AI-First by Design
Harmonic exists to help enterprises adopt AI safely and at scale. We hold ourselves to the same standard. Everyone at Harmonic actively uses AI tools to do their best work, from research and writing to building processes and automating workflows. We expect every new hire to bring curiosity about AI and a willingness to use it to work smarter, faster, and more creatively. For some roles, that means tinkering and staying open to new tools. For others, it means building entirely new systems with AI at the core. We'll be clear about what we expect for each role, and we'll give you the tools and support to get there.
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'll 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'll also drive continuous improvement of our existing model suite, using performance dashboards and direct customer feedback - including the opportunity to hear first-hand from customers - to prioritise retunes and sharpen detection accuracy.
- You'll stay abreast of the latest data science trends and techniques, continuously seeking ways to optimize models and datasets to enhance model performance.
- You'll collaborate effectively with engineers and security teams, fostering clear communication around data needs and ensuring seamless integration with our security solutions.
- You'll be directly contributing to the development of groundbreaking technology that empowers secure Generative AI adoption within enterprises.
- 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.
- Experience accelerating their work with AI tools (Claude Code, Cursor, or similar), whether that's writing code, debugging, researching, documenting, designing, or prototyping.
- A pulse on how AI is changing your domain and opinions about where it helps and where it doesn't.
- A mindset that rejects "the playbook" in favor of automating the mundane and rethinking legacy workflows.
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 categorization 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).
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
🌱 Flourish in the Unknown
We embrace new, unfamiliar situations that require initiative and rapid decision-making. We orient ourselves quickly and deliver results with minimal guidance.
🔥 Never Full
We raise our hands, take on challenges, and assist others whenever possible. We hunger for opportunities to learn and do more.
🤝 Perfect Harmony
We support one another to create cohesion and unity. We collaborate openly, share feedback honestly, and help everyone produce their best work