Penetration Tester (IC2)

AI-Augmented Pentesting: Human Expertise Where It Matters Most.

At OnSecurity, we're redefining cybersecurity through AI-augmented penetration testing - the perfect blend of AI efficiency and human ingenuity.

We deliver comprehensive, CREST-approved testing that saves time and money without compromising quality. Our all-in-one platform combines AI-driven automation with expert human insight to provide faster, more accurate results.

The outcome? Streamlined testing, actionable intelligence, and security at scale.

We're revolutionising how organisations protect their digital assets helping businesses stay secure, resilient, and one step ahead of threats.

We are based in the UK with employees working remotely. Some roles may have hybrid preference depending on the team. You can ask us about the best working hours and work setup in the recruitment process if there's something that's important to you. We try to be as flexible as possible.

All we ask is that everyone is online between our core hours of 10:00-16:00 (UK time) so that everyone overlaps for the majority of the day. It's up to you and your manager to find the right schedule that works for you and your team.

As a Penetration Tester, you'll play a central role in delivering high-quality, manual security testing to OnSecurity clients across a variety of sectors.

You'll take ownership of full test cycles; scoping, delivery, reporting, and client communication while helping to mentor junior testers and enhance OnSecurity's technical capabilities.

This role blends autonomy, technical depth, and real impact.

What you will be doing:

• Delivering web, API, mobile, and infrastructure penetration tests remotely.
• Identifying, analysing, and exploiting vulnerabilities beyond automated tools.
• Producing detailed, high-quality reports for developers and security teams.
• Collaborating with internal testers to refine methodologies and tooling.
• Contributing to TestNet and methodology development.
• Mentoring Junior testers.

What you won't be doing:

Following rigid scripts, you'll be encouraged to think critically and creatively.

Getting lost in bureaucracy, we empower our testers to deliver results via our intuitive portal

Within 1 month: Become familiar with our testing platform and delivery process.

Within 3 months: Lead your own engagements end-to-end and produce client-ready reports.

Within 6 months: Contribute to internal tooling, mentor junior testers, and help shape new methodologies.

This role is a great fit if you .

Minimum 2 years' experience delivering penetration tests in one or more disciplines.

Strong knowledge of OWASP Top 10 and common vulnerability classes.

Excellent written and verbal communication skills.

Enthusiastic team player who values collaboration and quality delivery.

What you will get for your hard work .

• A competitive compensation package. The salary range for this role is roughly £35k - £60k annually, depending on experience.
• Work at one of the fastest-growing Cyber Security Scale-Ups revolutionising pentesting.
• A clear progression plan. We want you to keep growing. That means trying new things, leading others, challenging the status quo and owning your impact, always with our complete support.
• Flexibility: We promote life-work balance at OnSecurity. We encourage everyone on our team to enjoy their life and ensure they have the balance they need to reach their full potential.
• Work where you work best. We're a distributed team. If you live in Bristol, we have a hybrid approach, if this is something that fits for your team. Otherwise, we are remote, and so we build our ways of working around this.

Other benefits:

• 30 days of paid annual leave, plus bank holidays
• Company Pension Scheme
• Private Health Insurance with Vitality
• Employee Assistance Program (EAP)
• Group Life Assurance (x4 salary)
• Enhanced Maternity, Paternity, and Adoption Leave
• Paid study leave for employees to level up their skills
• Mentorship and Coaching
• Annual Performance reviews and recognition for high performance
• Regular socials and activities, online and in-person.