Senior Web Security Engineer (ProdSec) in London

Senior Web Security Engineer

About i Proov i Proov provides science-based biometric solutions that enable the world’s most security-conscious organizations to streamline secure remote onboarding and authentication for digital and physical access.

Our award-winning liveness technology and i SOC offer unmatched resilience against deepfakes and generative AI threats while ensuring effortless, scalable user experiences.

Trusted by leading governments and enterprises, including the U.

Department of Homeland Security, U.

Home Office, Gov Tech Singapore, ING, and UBS, i Proov sets the standard in biometric identity assurance.

This global trust is built not only on our technology but on the strength of the people behind it.

For us, diversity at i Proov is about reflecting the customers we serve, holding the principles of equality and inclusion at the heart of everything we do and all that we stand for, embracing differences, creating possibilities, and growing together.

We aim to foster a culture where individuals of all backgrounds feel confident in bringing their whole selves to work, feel included, and their talents are nurtured, empowering them to contribute fully to our purpose.

The Role

Reports to

Head of Red Team

Location

UK (Flexible)

Comp

Negotiable (Base) + Company Performance Bonus (10%) + Share Options + UK i Proov Benefits

We're looking for an experienced Senior Web Security Engineer to design, build, and secure high-performance web applications that run in some of the world's most demanding environments.

In this role, you'll work at the intersection of browser security, Java Script runtimes, Web Assembly, anti-reverse engineering, and application hardening.

You'll help protect client-side applications against tampering, reverse engineering, and sophisticated attacks while developing highly optimized code that performs consistently across modern browsers and devices.

This is a hands-on engineering position for someone who enjoys solving difficult technical problems, understands the realities of client-side security, and is passionate about pushing the boundaries of what's possible in the browser.

How you can make an impact

You'll work on technically challenging problems that few engineering teams tackle—protecting sophisticated client-side applications in hostile environments.

You'll collaborate with experts in browser technology, security, cryptography, and systems engineering while building solutions used at global scale.

If you're passionate about Java Script internals, Web Assembly, browser security, and solving complex engineering problems, we'd love to hear from you.

• Design and implement secure Java Script and Web Assembly components for production web applications.
• Develop techniques to protect client-side code from tampering, reverse engineering, debugging, automation, and exploitation.
• Design and implement anti-tamper, integrity verification, and runtime protection mechanisms.
• Build high-performance Web Assembly modules using C++, Rust, or Assembly Script.
• Analyse browser behaviour, Java Script engines, and Web Assembly runtimes to identify security risks and performance opportunities.
• Research emerging attack techniques targeting web applications and develop practical mitigations.
• Collaborate closely with developers, product, and red teams to integrate security into the development lifecycle.
• Investigate vulnerabilities, perform root-cause analysis, and develop long-term remediation strategies.
• Contribute to technical architecture and mentor other engineers on secure development practices.
• What we would like to see from you

Within your first year, you'll have shipped secure, production-grade Java Script and Web Assembly components that real users depend on every day.

Along the way, you'll have introduced new techniques that materially strengthen our resistance to reverse engineering and client-side attacks, pushing the boundaries of what's possible in browser-based security.

You'll have found ways to make the application faster without ever compromising its security guarantees, proving that performance and protection aren't a trade-off.

Beyond the code itself, you'll have helped define the engineering standards that shape how we approach browser security and secure client-side architecture, leaving a lasting mark on how we build.

And by the end of that first year, you'll have become the person engineers across the organisation turn to when they need answers on web security, a trusted technical leader whose influence extends well beyond your own team.

• Technical Expertise
• Expert-level Java Script (ES6+) and Type Script.
• Strong experience developing production Web Assembly applications.
• Experience with Rust, C++, or another systems programming language used to produce WASM modules.
• Deep understanding of browser internals and modern web platform APIs.

• Experience securing client-side applications against

• Reverse engineering
• Runtime modification
• Instrumentation frameworks
• Code injection
• Experience with secure software architecture.
• Security Knowledge

Experience in several of the following

• Java Script de-obfuscation and obfuscation techniques
• WASM binary analysis
• Static and dynamic analysis
• Anti-debugging techniques
• Anti-tamper technologies
• Runtime integrity verification
• Secure code signing and integrity checking
• Software protection techniques
• Secure SDLC practices
• Engineering Experience
• 5+ years of software engineering experience.
• Experience designing highly performant browser-based applications.
• Strong testing, debugging, and profiling skills.
• Experience working with CI/CD pipelines and automated security testing.
• Comfortable working across Windows, mac OS, Linux, and mobile browsers.
• Excellent communication skills with the ability to explain complex technical concepts clearly.
• Nice to Have
• Experience with V8, Spider Monkey, Java Script Core, or Chromium internals.
• Knowledge of Web GPU, Web RTC, or Web Codecs.
• Experience with binary instrumentation and compiler toolchains.
• Experience building SDKs or developer platforms.
• Knowledge of mobile browser security.
• Experience with biometrics, identity verification, or fraud prevention technologies.
• Contributions to open-source security tools or security research publications.

Benefits

• 25 days Annual Leave, plus 8 Bank Holidays (more holiday with service - up to an extra 5 days off per year based on your continuous service)
• Growth Shares allocated after passing probation (6 months of service)
• Salary sacrifice schemes including: Pension, Cycle To Work and Electric Car Scheme
• Nursery Sacrifice Scheme
• Work Overseas Perk - Work globally for up to 2 weeks
• Life Assurance
• Smart Health - Access to private GP, Psychologist, Nutritionist along with tailored fitness plans for both you and your family
• Benefit from personalized 1:1 career coaching with our in-house Occupational Psychologist
• Award winning L&D platform with personal allocated training budgets
• Enhanced paid family leave
• Pension - 5% employee, 3% employer
• Flexible hybrid working environment
• Free Barista Coffee/Tea, biscuits with fruit in the We Work office
• Free access to We Work discounts and free online well-being sessions
• Vitality Health - a range of options available on this below

The Vitality Programme includes a number of reward benefits that all employees have access to as part of the plan, for example:

• Private Health cover including Dental, Optical, and Audiology
• 50% off monthly gym memberships
• Apple watches significantly discounted based member vitality status
• Half price trainers with Runners Need
• Weekly rewards – Free coffee with Café Nero
• Monthly rewards – Free Cinema ticket
• Discounts on travel with Expedia (hotels) and Mr & Mrs Smith with discounts getting greater throughout the year based on a members vitality status
• Amazon prime free months based on activity
• Up to 25% cashback at Waitrose when buying healthy foods
• 75% off stays at Champneys Health Spas
• Allen Carr’s £299 no smoking programme for free
• Access to Vitality Healthy Mind with 30% off Headspace subscriptions and the ability to earn Vitality points for using Buddhify, Calm and Headspace
• Discounts on Weight Watchers
• 50%-80% off Comprehensive Private Health screenings
• Our Culture & Recruitment Process

At i Proov, we're incredibly proud of the culture we've carefully curated.

Our culture enables diverse thought, curiosity and innovation.

Our team strives to do everything to the highest standard possible to achieve the remarkable.

To do that we need different perspectives, experiences and ideas alongside an environment where these are welcomed - we want everyone to feel confident in bringing their full capabilities to work.

We firmly believe psychological safety is key to building and nurturing great teams.

We’re a small and dynamic company, that means having the right skills is important, and we know that our best work emerges when people feel secure, welcomed and respected.

As an equal opportunities employer, we encourage applications from people of all backgrounds.

We’re committed to building a workforce that is representative of the people we serve.

We will not put someone at a disadvantage or treat them less favourably because of race, color, national origin, ancestry, age, disability, creed, religion or belief, sex, sexual orientation, gender reassignment, marriage or civil partnership, or pregnancy and maternity.

Our goal is to find people who are passionate about creating a safer, more secure world.

Our recruitment process is designed to be fair and transparent, focusing solely on your qualifications, competence, and suitability for the role.

We review all applications carefully and will be in touch with shortlisted candidates regarding the next steps in our interview process.

If you need an adjustment for a disability or any other reason during the hiring process, please send a request to careers@iproov. com