Instil

About the Company

At Instil, we help technology brands transform, innovate and disrupt their markets with secure, category-defining software. Our services include product development, delivering next-generation digital solutions; cyber security, helping teams protect against emerging cyber threats; and artificial intelligence, unlocking the potential of your data and people.

Listed Jobs

Company Name

Instil

Job Title

Principal Penetration Tester

Job Description

**Job title** Principal Penetration Tester **Role Summary** Senior, hands‑on security professional responsible for leading and delivering complex penetration testing engagements across infrastructure, cloud, web, and mobile platforms. Coordinates all phases of testing, mentors junior staff, and drives the evolution of testing methodologies. **Expectations** - CHECK Team Lead (CTL) status (Infrastructure preferred, Applications acceptable). - Current UK Security Clearance (SC). - Minimum 5 years of proof‑of‑concept penetration testing experience. - Proven track record of delivering large, complex engagements to diverse industries. **Key Responsibilities** 1. Conduct end‑to‑end penetration tests on infrastructure, cloud, web, and mobile applications. 2. Manage engagements from scoping and kick‑off to delivery and client debrief. 3. Produce detailed, actionable vulnerability reports and remediation recommendations. 4. Research and integrate emerging offensive techniques into the methodology. 5. Automate repetitive tasks and optimize testing processes through scripting. 6. Mentor and coach junior testers, supporting skill development and career growth. 7. Enhance tools and procedures to maintain cutting‑edge services. 8. Provide subject‑matter expertise for pre‑sales activities. 9. Communicate findings to technical and non‑technical stakeholders. 10. Contribute to thought‑leadership via blogs, white papers, or speaking engagements. **Required Skills** - Advanced proficiency in cloud security reviews (AWS, Azure, GCP). - Deep expertise in web, mobile, and network penetration testing. - Strong knowledge of Linux, Windows, and Active Directory environments. - Skilled with tools: BurpSuite Pro, Nmap, Nessus, Metasploit, Kali Linux. - Advanced scripting (Python, Shell). - Excellent written and verbal communication and report‑writing abilities. **Required Education & Certifications** - CHECK Team Lead (CTL) accreditation (preferred Infrastructure). - UK SC Security Clearance. - Minimum 5 years hands‑on penetration testing. - Certifications: OSCP, CSTL/CCT, Cyber Scheme, CREST (highly desirable). - UK Cyber Security Council Chartership (Principal level) (desirable). ---

Belfast, United kingdom

On site

Senior

05-02-2026

Company Name

Instil

Job Title

Lead Penetration Tester - CTL App

Job Description

Job Title: Lead Penetration Tester – CTL App Role Summary Senior hands‑on penetration tester responsible for planning, executing, and signing off complex web application and API security engagements. Leads a team, mentors junior staff, and advances testing tools and methodologies while ensuring high‑quality, actionable deliverables to clients. Expactations - Deliver end‑to‑end engagement ownership from scoping to client debrief. - Maintain up‑to‑date knowledge of emerging application‑level threats. - Mentor junior testers on web app testing techniques and report quality. - Support pre‑sales activities as a web‑app security subject‑matter expert. - Contribute to thought leadership through published content or speaking. Key Responsibilities - Lead & execute web application and API penetration tests for diverse industry clients. - Conduct in‑depth manual testing of authentication flows, APIs, and business logic. - Produce detailed, actionable vulnerability reports with remediation guidance. - Implement automation (scripting, tooling) to increase test efficiency. - Maintain and evolve in‑house application‑focused testing tools and methodologies. - Sign off on all findings and ensure compliance with engagement objectives. - Communicate findings across technical and non‑technical stakeholders. - Assist in pre‑sales discussions and solution design as needed. Required Skills - CHECK Team Lead (CTL) status – Web Applications. - Current UK SC Clearance. - Minimum 5 years of web application/API penetration testing, including leadership of engagements. - Deep expertise in web application, API, and authentication testing methodologies. - Proficient with Burp Suite Pro and supporting tools (Nmap, Kali). - Strong scripting skills – Python, Shell, or equivalent. - Excellent report‑writing and communication abilities. - Working knowledge of cloud environments (AWS, Azure, GCP) related to application security. Required Education & Certifications - Relevant degree in Computer Science, Information Security, or related field (preferred). - CHECK Team Lead (CTL) – Web Applications certification. - Current UK Security Clearance (SC).

Belfast, United kingdom

Remote

Senior

05-03-2026