Data Scientist

• Data Scientist
• Harmonic Security
• Type: Mid-level industry position
• Attendance: On-Site
• Posted on: 04 August 2026
• Application Deadline: 17 August 2026

Join Harmonic Security as a Data Scientist, contribute to AI governance and cybersecurity.

AI is being run everywhere, by humans and agents.

Harmonic Security governs all of it.

The AI Governance and Control (AIGC) platform understands user / agent intent and data context in real time, giving security teams visibility and control across every tool and workflow so companies can move faster with AI while minimizing risk.

We operate in one of the fastest-moving spaces in tech: the emerging intersection of AI and cybersecurity.

It's a market still being defined, and we're among the first to build natively for it - protecting sensitive data in real time, at the endpoint, with minimal friction for the teams using it.

Enterprises get full visibility and control.

Their people get to innovate without guardrails slowing them down.

Named to the Rising in Cyber 2026 list, Harmonic is gaining serious recognition and serious traction.

We're led by deep cybersecurity expertise and backed by investors who know the space: N47, Ten Eleven Ventures, and In-Q-Tel.

As AI adoption inside the enterprise accelerates, the ability to safely observe, control, and enforce policy in real time isn't a nice-to-have.

It's mission-critical infrastructure.

That's what we build.

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 fast.

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 help advance our mission to secure Generative AI adoption by building and continuously improving the detection models at the heart of our product - curating high-quality training datasets and tuning production models informed by real-world customer feedback.

• What You’ll Do
• You’ll build and improve sensitive data detection models end-to-end - defining new sensitive data categories, curating training and evaluation datasets, training and validating models, and shipping production-ready detectors.
• Once models are live, you’ll continuously improve our existing suite using model performance metrics and direct customer feedback to prioritise retunes and sharpen detection accuracy.
• You’ll communicate clearly and proactively in a remote/hybrid team - able to explain trade-offs, make recommendations, and bring engineering, security, and product partners along in decisions without slowing momentum.
• You’ll stay current on techniques that materially improve model and dataset quality, and you'll be directly contributing to the development of groundbreaking technology that empowers secure Generative AI adoption within enterprises.
• You'd Be A Great Fit if You
• You’ve taken classification / NLP models from idea to production and owned them after launch - monitoring performance, tuning on real-world feedback, and improving results over time (not just training and handing off).
• You have strong applied NLP experience: transformers and embeddings, when fine-tuning makes sense, and when a simpler classical approach wins.
• You’ve built and managed high-quality training and evaluation datasets from messy real-world data - making hard labelling/taxonomy calls, and you can point to how dataset quality moved model performance.
• You run rigorous evaluation and care about precision/recall trade-offs, so we know a model is better before customers do.
• You’re expert in Python and comfortable in the modern ML stack (e. g. Py Torch, Hugging Face, scikit-learn).
• You’re a clear communicator who collaborates well across a remote/hybrid team, and you have a bias for shipping: pragmatic decisions, fast iteration, and incremental delivery.
• Bonus Points If You Have
• Experience in data security / sensitive-data classification, or adjacent applied security problem spaces.
• Experience working directly with customers/end-users to understand the problem domain and validate improvements.
• Experience operating ML systems in cloud environments (e. g. AWS).
• 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.

• Why Join Us
• This isn't just a job - it's a chance to help define a category.

Harmonic Security was named to the Rising in Cyber 2026 list, and we're just getting started.

We're building at the intersection of AI and security, carving out an emerging market where the rules haven't been written yet, and the people who join now will write them.

• 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.
• Recognized momentum - We made the Rising in Cyber 2026 list, a signal that the market is taking notice.
• Rare market opportunity - Join early in a category-defining company at the convergence of AI and security, where your work directly shapes how enterprises tackle one of the biggest unsolved problems in tech.
• Competitive pay and meaningful equity - A real stake in Harmonic's success, not a token gesture.
• Comprehensive benefits - 401K, pension plan, generous PTO, and flexible hybrid work.
• A small, high-trust team that values transparency, creativity, and continuous learning - no politics, no bureaucracy.
• Thoughtful leadership - that cares deeply about your growth, not just your output.
• Annual global off-sites - past trips include Lisbon, Portugal and Nashville, TN.
• Real ownership - you'll shape the product, the culture, and the direction of the company from day one.
• More Information
• Visit Website
• London, UK
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