Senior Security Engineer - Mobile & Application Security

Job Title: Senior Security Engineer – Mobile & Application Security

Duration: 12 months + extension (Permanent is also considered if preferred)

Location: UK - fully remote acceptable, hybrid much preferred

IR35: Outside IR35

Industry: Leading financial technology company

Project Details

They are looking for two Senior Security Engineers with strong experience in mobile application security to help improve security across mobile and backend platforms. You will work hands-on with engineering and product teams to identify, design and implement security controls throughout the development lifecycle.

Responsibilities

• Mobile application security across iOS and Android, including authentication and authorization mechanisms, secure data storage, runtime protections and hardening techniques.
• API security, including OAuth and token-based authentication, abuse prevention, rate limiting and business logic vulnerabilities.
• Conduct threat modelling, design reviews and hands-on security reviews of mobile and backend systems.
• Work closely with product managers and mobile/backend engineers to embed security into day-to-day development.

Requirements

• Proven experience as an Application Security Engineer, Product Security Engineer or Mobile Engineer with a strong focus on application security.
• Strong understanding of mobile-to-API interaction patterns and common attack vectors in modern mobile applications.
• Strong hands-on experience across mobile and API security.
• Ability to work hands-on and pragmatically with engineering teams.
• Experience with React Native internals is nice to have.