Senior Penetration Tester

The Role

We’re looking for a Senior Penetration Tester to join our growing security team, delivering high‑quality testing across web applications, networks, cloud environments, and APIs for a diverse range of clients.

This is a hands‑on role where you’ll help organisations identify and remediate real‑world security risks. You’ll also have the opportunity to contribute to improving our tooling, methodologies, and knowledge sharing within the team.

If you’re passionate about offensive security and enjoy practical, problem‑solving‑led work in a collaborative environment, we’d love to hear from you.

What You’ll Be Doing

• Deliver penetration testing engagements across:

  • Web applications

  • Network and infrastructure

  • Cloud environments

  • APIs and supporting services

• Identify vulnerabilities, validate exploitability, and clearly articulate risk.

• Produce concise, actionable reports suitable for both technical and non‑technical stakeholders.

• Support clients with vulnerability remediation and technical explanations.

• Contribute to the evolution of testing methodologies and internal tooling.

• Collaborate closely with other testers and support the development of junior team members.

Essential Skills & Experience

• 2+ years’ experience in a hands‑on penetration testing role.

• Strong experience with web application and network/infrastructure testing.

• Solid understanding of common vulnerability classes (e.g. OWASP Top 10).

• Good working knowledge of Linux, Windows, and Active Directory environments.

• Experience testing or reviewing cloud environments (AWS, Azure, GCP).

• Proficiency with common tooling such as:

  • Burp Suite

  • Nmap

  • Nessus (or equivalent)

  • Kali Linux

• Scripting experience in Python, Bash, or similar, for automation or custom tooling.

• Ability to clearly communicate technical findings and risk.

Nice to Have

• Relevant security certifications (e.g. OSCP, OSWE, CRTO, Cyber Scheme incl. CSTM or CSTL).

• UK Security Clearance

• Experience with capture‑the‑flag platforms, labs, or challenge‑based learning.

• Mobile application testing experience.

• Prior consultancy or client‑facing experience.

Why Join Instil?

At Instil, we believe great work starts with happy, motivated people. That’s why we’ve built a benefits package that supports your wellbeing, growth, and life outside of work, because when you thrive, so do we.

• Recognition That Matters: A discretionary annual performance bonus that rewards your impact and contribution to our success.

• Flexibility Built In: Flexible working arrangements and summer hours, because life isn’t 9 to 5, and balance matters.

• Financial Security: A highly competitive pension scheme with generous employer contributions, private healthcare, and life assurance for peace of mind.

• Health & Wellbeing: Employee Assistance Programme, mental health support, cycle-to-work scheme, and regular social events to keep our culture vibrant.

• Time to Recharge: 35 days holiday, enhanced maternity pay, and family-first policies so you can focus on what matters most.

• Learning Never Stops: From courses to certifications, we’ll invest in your development so you can keep growing and shaping what’s next.

• Community & Culture: Opportunities to volunteer, give back, and be part of initiatives that make Instil a truly inclusive and connected workplace.

And that’s just the start, drop us a note to find out more.

Company Description

Instil has been delivering world-class software engineering and technology solutions for over 20 years, trusted by global brands to solve complex challenges and drive innovation. From modernising legacy systems to building cutting-edge applications, we help our clients navigate an ever-changing digital landscape with confidence and agility.

We’re proud to be an award-winning employer, reflecting how our people are at the heart of everything we do:

• Recognised as a Great Place to Work® for three consecutive years, and in 2024 ranked in the Top 20 Best Workplaces in the UK for medium-sized companies.

• Winner of Company of the Year at the Digital DNA Awards 2022, celebrating excellence in Northern Ireland’s tech sector.

Driven by a love for technology and a commitment to excellence, we bring together people who want to make a difference. We’ll support your journey, because your success is part of ours.

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