Application Security Engineer JavaScript

Client Server; City Of London; Hybrid; GBP 72,000 - 88,000; Full time

Benefits offered by this job

Equity

Bonus

Job summary

Client Server in London is seeking a security-focused professional to lead offensive web security efforts. You willCollaborate with developers to embed secure practices, perform penetration testing, and guide secure coding while bridging Security and Engineering.

The role combines hands-on testing with collaboration across teams, in a hybrid London-based setup with remote options and opportunities for equity and bonus.

Qualifications

• We have strong experience in web application security and offensive security testing.
• Hands-on expertise in penetration testing and reverse engineering.
• Deep understanding of modern web security vulnerabilities and mitigation techniques.
• Commercial JavaScript experience, with TypeScript knowledge highly desirable.
• Comfortable writing and reviewing production code, not just identifying vulnerabilities.
• Collaborative and pragmatic, and able to work closely with engineering teams.

Responsibilities

• Collaborate with the web development team to center security in all web apps.
• Join a specialist security team and focus on offensive web security.
• Bridge between Security and Engineering.
• Perform penetration testing, reverse engineering and vulnerability assessments.
• Identify security risks and work with developers to build secure, resilient web apps.
• Provide expert guidance on secure coding practices.
• Influence architecture and design decisions.
• Embed security throughout the software development lifecycle.

Skills

JavaScript

TypeScript

Penetration testing

Reverse engineering

Web security

Collaborative work

Job description

Salary: £80,000 - 80,000 per year

Requirements:

• We have strong experience in web application security and offensive security testing.
• We have hands-on expertise in penetration testing and reverse engineering.
• We have a deep understanding of modern web security vulnerabilities and mitigation techniques.
• We have commercial JavaScript experience, with TypeScript knowledge highly desirable.
• We are comfortable writing and reviewing production code, not just identifying vulnerabilities.
• We are collaborative and pragmatic, and able to work closely with engineering teams.

Responsibilities:

• We collaborate closely with the web development team to ensure security is at the centre of all web-based applications.
• We join a specialist security team and focus on offensive web security.
• We act as the bridge between Security and Engineering.
• We perform penetration testing, reverse engineering and vulnerability assessments.
• We identify security risks and work closely with developers to build secure, resilient web applications from the ground up.
• We provide expert guidance on secure coding practices.
• We influence architecture and design decisions.
• We help embed security throughout the software development lifecycle.

Technologies:

• AI
• Computer Vision
• JavaScript
• Security
• TypeScript
• Web

More:

We are a global leader in Computer Vision, AI and biometric identity, and our technology protects governments, critical infrastructure and some of the worlds largest enterprises against identity fraud, deepfakes and sophisticated cyber threats. This is a highly collaborative role based in London with remote working, where we meet up in the London office approximately twice a month for innovation sessions and team meetings. We offer a salary of up to £80k, plus bonus, equity and excellent career progression.

last updated 36 week of 2026