--- title: 'Senior Penetration Tester - CTM at Instil Software Ltd' canonical: 'https://feeny.ai/job/senior-penetration-tester-ctm-instil-software-ltd-belfast-wstkamwh35vy' type: 'job' last_seen: '2026-09-15' --- # Senior Penetration Tester - CTM at Instil Software Ltd - **Company:** Instil Software Ltd - **Location:** Belfast, United Kingdom - **Employment:** full-time - **Work type:** remote - **Posted:** 2026-07-09 - **Last confirmed live:** 2026-09-15 - **Apply:** https://jobs.ashbyhq.com/instil/8855f8d0-0247-49b2-8f06-b0560c5e4101/application **Skills:** BurpSuite Pro, Nmap, Nessus, Kali Linux, Python, Shell, Linux, Windows, Active Directory, Web application penetration testing, Network penetration testing, Cloud security reviews, Hack the Box, Capture the Flag simulations > Instil is seeking a Senior Penetration Tester with CHECK Team Member status and UK Security Clearance to conduct infrastructure, cloud, and application security assessments. The role involves identifying security weaknesses, mentoring junior staff, and utilizing tools like BurpSuite and Kali Linux. ## Job description We are looking for a Senior Penetration Tester with CHECK to join our growing team. You will play a critical role in delivering high-quality penetration testing engagements across infrastructure, cloud, web, and mobile applications for a diverse range of clients, including software, fintech, manufacturing, engineering, legal, and public sector organisations. This is a hands-on role where your expertise will help identify and remediate security weaknesses, while contributing to the development of our methodologies and mentoring junior testers. If you’re passionate about offensive security and want to work on varied, challenging projects in a supportive environment, we’d love to hear from you. Essential Skills - CHECK Team Member (CTM) status - Current UK Security Clearance. - At least 2+ years of penetration testing experience. - Strong experience with web application and network penetration testing methodologies. - In-depth knowledge of operating systems (Linux, Windows, Active Directory). - Familiarity with cloud environments and ability to perform cloud security reviews. - Proficiency with tools such as BurpSuite Pro, Nmap, Nessus, and Kali Linux. - Knowledge of scripting languages (Python, Shell, etc.). Nice-to-Have - CHECK Team Lead (CTL) status (Infrastructure or Applications). - Relevant certifications (OSCP, Cyber Scheme). - Experience with Hack the Box or Capture the Flag simulations. 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. #LI-PR1 #InstilCareers ## About Instil Software Ltd ## Company Overview - **One-liner**: Instil combines deep engineering expertise with agentic workflows, cyber security, and AI transformation to help organisations build better software faster. - **Entity Type**: Private (bootstrapped) - **Headquarters**: Belfast, County Antrim, Northern Ireland, UK - **Founded**: 2005 - **Founders**: Not publicly available ## Core Business - **Primary industry/industries**: Software engineering consultancy, cyber security, AI transformation, technical training - **Target customers**: B2B – from ambitious start-ups to global enterprises - **Mission or purpose statement**: Unlocking the potential of people and technology ## Products & Services - **Agentic Product Engineering**: Combines product engineering expertise with an agentic workforce to build new products and modernise legacy platforms with AI-driven delivery. (Service) - **Cyber Security**: Embeds cyber security into an organisation’s culture, keeping it human-centred, practical and proactive. (Service) - **AI Transformation**: Prepares data, people and products to move faster and solve more complex problems with AI. (Service) - **Technical Training**: Provides education and upskilling in software engineering, security, and AI. (Service) ## Market Standing - **Valuation/Market Cap**: Not disclosed - **Key Metric**: Total employees ~130 (as of latest data) - **Notable Investors/Partners**: Not publicly available; works with “some of the world’s best known technology brands” (specific names not listed) - **Growth Signals**: Active job openings (8 roles listed), emphasis on agentic workflows and AI-driven delivery – a growing market space. No headcount growth rate disclosed. ## Competitive Advantages - Longevity (founded 2005) with consistent focus on quality software engineering - Unique combination of agentic product engineering, cyber security, and AI transformation under one roof - Human-centred approach to security, differentiating from purely technical providers - Hybrid work model with a strong local base in Belfast, offering stability and culture ## Strategic Focus - Scaling agentic workflows across the full product lifecycle - Deepening AI transformation capabilities for clients - Maintaining a multi-disciplinary team of engineers, designers, educators, and security specialists ## Why Work Here - **Culture**: Diverse, multi-disciplinary team focused on positive impact; flexible working hours, summer hours, and generous PTO - **Remote/Hybrid Policy**: Hybrid – employees work from the Belfast office with some onsite presence; not fully remote - **Notable Perks**: Private healthcare, cycle to work scheme, annual bonus, generous parental leave, family & childcare benefits, learning & development budget - **Engineering culture**: Emphasis on continuous learning, agentic methodologies, and working with cutting-edge tech stacks ## Sources 1. [instil.co](https://instil.co/) 2. [careers.instil.co](https://careers.instil.co/) 3. [instil.co about](https://instil.co/about) 4. [builtin.com/company/instil-instilco](https://builtin.com/company/instil-instilco) ## Other roles at Instil Software Ltd - [Principal Software Engineer](https://feeny.ai/job/principal-software-engineer-instil-software-ltd-belfast-mmyvgy6pp5y1) — Belfast, United Kingdom - [Fullstack Engineer](https://feeny.ai/job/fullstack-engineer-instil-software-ltd-belfast-wfn58sx5v3em) — Belfast, United Kingdom - [Data Engineer (Python/ AWS)](https://feeny.ai/job/data-engineer-python-aws-instil-software-ltd-belfast-zwmk88ah3cmw) — Belfast, United Kingdom - [Register Your Interest](https://feeny.ai/job/register-your-interest-instil-software-ltd-belfast-vc1vat1ass4c) — Belfast, United Kingdom