Founding Security Researcher

CodeWall; Greater London; Hybrid; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Competitive salary

Meaningful equity

London office with hybrid model

Direct access to founders and peers

Job summary

CodeWall is seeking a Security Researcher & Penetration Tester to help define the world’s best AI hacker. You will lead real penetration tests, research vulnerabilities, and attack our own platform while shaping scalable AI capabilities for production use.

You’ll work directly with founders, engineers, and customers, owning offensive methodology, research agenda, and security culture. London office with a hybrid model, typically 3–4 days onsite.

Qualifications

• Significant professional experience in penetration testing or vulnerability research.
• Strong expertise in web/API security and source-code review optional.
• Ability to lead complex engagements and communicate findings to technical and executive audiences.
• Curiosity and initiative to operate in an early-stage company.
• Knowledge of AI/ML security concepts is a plus.

Responsibilities

• Lead authorised penetration-testing engagements from scoping through execution, reporting and remediation.
• Test web applications, APIs, cloud environments, enterprise infrastructure and AI systems.
• Validate and triage findings produced by AI agents, eliminating false positives and proving real-world impact.
• Penetration-test CodeWall’s platform and infrastructure as our most demanding internal customer.
• Conduct original vulnerability research across authorised targets and open-source software.
• Define new attack techniques, testing strategies and benchmarks for our AI agents.
• Convert tools and expertise into scalable capabilities.
• Collaborate with technical teams, security leaders and senior customer stakeholders.
• Help establish a world-class offensive-security team and raise the bar for everyone.

Skills

Penetration testing

Web security

API security

Vulnerability research

AI security

Job description

Security Researcher & Penetration Tester

Build the hackers that will shape cybersecurity

CodeWall is building autonomous offensive-security agents—AI systems that attack real environments, prove exploitability and produce findings security teams can act on.

We’ve raised $4 million in pre-seed funding—the largest ever for a UK cybersecurity startup—and our technology is already uncovering critical vulnerabilities in systems operated by sophisticated organisations.

Now we’re looking for an exceptional security researcher and penetration tester to help define what the world’s best AI hacker should be.

Come hack the planet with us.

The opportunity

This is not a role where you simply review scanner output.

You’ll lead real penetration tests, research vulnerabilities, attack our own platform and help turn expert human tradecraft into scalable AI capabilities. You’ll influence how our agents reason, chain attacks, validate findings and learn from failure.

As one of our first security hires, you’ll have genuine ownership of our offensive methodology, research agenda, product direction and security culture.

You’ll work directly with founders, engineers and customers—and help build the team around you.

What you’ll do

• Lead authorised penetration-testing engagements from scoping through execution, reporting and remediation.
• Test web applications, APIs, cloud environments, enterprise infrastructure and AI systems.
• Validate and triage findings produced by our agents, eliminating false positives and proving real-world impact.
• Penetration-test CodeWall’s platform and infrastructure as our most demanding internal customer.
• Conduct original vulnerability research across authorised targets and open-source software.
• Define new attack techniques, testing strategies and benchmarks for our AI agents.
• Convert your tools, techniques and intuition into capabilities that operate at scale.
• Work directly with technical teams, security leaders and senior customer stakeholders.
• Help establish a world-class offensive-security team and raise the bar for everyone around you.

What we’re looking for

• Significant professional experience in penetration testing, offensive security or vulnerability research.
• Strong expertise in web application security, API security, application security or source-code review.
• The ability to lead complex engagements independently and communicate findings clearly to both technical and executive audiences.
• Depth in at least one additional area, such as cloud security, internal networks, Active Directory, CI/CD or software supply chains.
• Excellent vulnerability analysis, problem-solving skills and attention to detail.
• A practical understanding of how AI can improve offensive security—and where human judgement remains essential.
• Curiosity, initiative and the confidence to operate in an early-stage company where you’ll help create the playbook.

Especially valuable

• You build offensive-security tools, automation or research frameworks.
• You have published CVEs or GHSAs, contributed to bug-bounty programmes or achieved strong results in CTFs.
• You understand AI/ML security, LLM red teaming, prompt injection or agentic systems.
• You can review code across multiple languages.
• You’ve presented research, contributed to open source or earned recognition in the security community.
• You’ve mentored, hired or developed other security practitioners.

We care more about how you think and what you can discover than ticking every box. If you’re not a perfect match on paper but believe you’d be dangerous here, we want to hear from you.

What we offer

• A chance to shape the future of offensive security from the ground up.
• Meaningful ownership as one of our earliest security hires.
• Competitive salary and meaningful early-stage equity.
• Direct access to founders and exceptional technical peers.
• Hands-on work across real customer environments, original research and AI product development.
• London office with a hybrid model: typically 3–4 days per week together.

Read our manifesto and research at codewall.ai.

If you want to help build the AI that can out-hack the world’s best human testers, apply now.