Full Stack Engineer (£120k-£135k + Equity) at $2.3M seed-funded AI cybersecurity startup

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Job Title

Full Stack Engineer

Salary

£120k-£135k + Equity

Company Description

$2.3M seed-funded AI cybersecurity startup transforming vulnerability management

Job Description

You will join as a core engineer building an AI engine that prioritizes critical security threats. Working alongside a founder from HackerOne, you will bridge the gap between automated scanning and real-world attacker logic, developing sophisticated ML pipelines and agentic AI features to help organizations defend themselves at scale.

Location

London, UK

Why this role is remarkable

• Work directly with a founder who led Hacker R&D at HackerOne and managed programs for the UK Ministry of Defence and FTSE 100 companies.
• Massive ownership in a small team of 6, backed by 6 Degrees Capital and advisors from DeepMind, Cisco, and 1Password.
• Opportunity to shape an AI-native product in a $17B+ market, moving beyond simple API wrappers to genuine model training and evaluation.

• Build and maintain full-stack features using a Python/Prefect backend and React frontend, handling everything from authorization to production debugging.
• Own the ML lifecycle, including training models, building evaluation pipelines, and shipping agentic AI features to automate vulnerability analysis.
• Collaborate directly with customers to identify pain points, rapidly prototype solutions, and ship impactful security tools in a fast-paced environment.

• Has 2-6 years of professional engineering experience with strong Python fundamentals and a proven track record of shipping production software.
• Possesses genuine depth in Machine Learning, understanding model training and evaluation techniques rather than just consuming third-party APIs.
• Exhibits a growth mindset and curiosity, thriving in high-autonomy startup environments and valuing engineering craft over rigid processes.

Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.

And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate.

Next steps

Step 1. Visit the job listing.

Step 2. Click 'Talk to Jack', or go straight there: https://www.jackandjill.ai/jobs/full-stack-engineer-120k-135k-equity-at-2-3m-seed-funded-ai-cybersecurity-startu-ddabd12c-ef8a-4c59-a03d-095e5765fca1?utm_source=linkedin&utm_medium=job_post&utm_campaign=featured_role_ddabd12c-ef8a-4c59-a03d-095e5765fca1

Step 3. Talk to Jack so he can understand your experience and ambitions.

Step 4. Jack will make sure Jill (the AI agent working for the company) considers you for this role.

Step 5. If Jill thinks you're a great fit and her client wants to meet you, they will make the introduction.

Step 6. If not, Jack will find you excellent alternatives. All for free.

We never post fake jobs

This isn't a trick. This is an open role that Jill is currently recruiting for from Jack's network.

Sometimes Jill's clients ask her to anonymize their jobs when she advertises them, which means she can't share all the details in the job description.

We appreciate this can make them look a bit suspect, but there isn't much we can do about it.

Give Jack a spin! You could land this role. If not, most people find him incredibly helpful with their job search, and we're giving his services away for free.