Senior Offensive Security Engineer

London/Cardiff/UK Remote | £76,500 - £90,000 + Incentive awards tied to your performance + Benefits ✨

Our Offensive Security team⭐

You'll be joining Monzo’s Offensive Security team, part of our wider Security collective. We're a team of curious, hands on security professionals who think like attackers to help keep Monzo and our customers safe. We work across everything from customer facing products and mobile apps to cloud infrastructure, internal systems, and emerging technologies like AI.

Our role is to find weaknesses before others do. Through security testing, red and purple teaming, and adversarial research, we uncover vulnerabilities, demonstrate real-world impact, and help teams build more secure systems. We work closely with engineers and security partners across Monzo, bringing an attacker mindset into the room and helping shape security decisions through collaboration, curiosity, and practical expertise.

You’ll play a key role by...

• Leading offensive security projects from initial idea through to execution and reporting
• Simulating real world attacks to uncover vulnerabilities across our systems, infrastructure, and products
• Partnering with engineering and security teams to improve detection, response, and resilience
• Bringing an attacker mindset into conversations - asking “what if?” and challenging assumptions
• Producing proof-of-concept exploits to clearly demonstrate risk and drive meaningful fixes
• Mentoring others in the team and acting as a highly independent technical lead on complex engagements

We’d love to hear from you if…

• You have a strong attacker mindset and are naturally curious about how systems can be broken
• You’ve got hands on experience in offensive security across areas like web, mobile, cloud, or infrastructure
• You’re comfortable working across modern tech stacks (e.g. Kubernetes, AWS/GCP, microservices) or excited to learn
• You can take ownership of ambiguous problems and drive them through to impactful outcomes
• You enjoy collaborating with others and influencing teams to think more securely
• You’re experienced in security testing and/or have relevant certifications (e.g. OSCP, CREST)

Not ticking every box? That’s totally okay! Studies show that women and people of colour might hesitate to apply unless they meet every single requirement. At Monzo, we’re dedicated to creating a diverse and welcoming team. If you’re passionate about this role and keen to learn and grow with us, we encourage you to apply— even if you don’t have everything that's listed just yet. Drop us your application, we’d love to hear from you!

What’s in it for you
£76,500 - £90,000➕Incentive awards tied to your performance
This role can be based in our London office, but we're open to distributed working within the UK (with ad hoc meetings in London)
⏰ We offer flexible working hours and trust you to work enough hours to do your job well, and at times that suit you and your team.
£1,000 learning budget each year to use on books, training courses and conferences.
We will set you up to work from home; all employees are given Macbooks and for fully remote workers we will provide extra support for your work-from-home setup.
➕ Plus lots more! Read our full list of benefits.

The application journey has 3 key steps

• 30 min recruiter call
• 30 min call with the hiring manager
• 2 hours of technical and behavioural interviews

This process should take around 3-4 weeks - your schedule is really important to us, so we promise to be as flexible as possible!

We have some guidelines on using Artificial Intelligence (AI) to ace an application and interview at Monzo. You can read them here.

We’ll only close this role once we have enough applications for the next stage. Please submit your application as soon as possible to make sure you don’t miss out.

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